feat(balance): support priced kind in AccountForm + SnapshotLineRow

- AccountForm now exposes a 'category' variant with a kind selector
  (simple | priced); the legacy 'account' variant is unchanged
  modulo the new symbol-required-for-priced UI guard.
- SnapshotLineRow dispatches on account.category_kind:
  * simple variant unchanged from #146
  * priced variant: quantity + unit_price inputs + read-only
    computed value rendered live (qty × price, 2 decimals) +
    [Manuel] attribution tag
- useSnapshotEditor extends state with pricedValues map, exposes
  setLineQuantity / setLineUnitPrice handlers, prefill copies
  quantity but leaves unit_price blank (per spec-decisions row),
  save() builds mixed simple+priced batches.
- SnapshotEditor + SnapshotEditPage thread the new priced state.
- Total line at the top of SnapshotEditPage now sums simple + priced
  contributions live as the user types.

Refs #140

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/balance/AccountForm.tsx

@@ -1,20 +1,31 @@
-// AccountForm — variant=account (Issue #138 / Bilan #1a).
+// AccountForm — account or category variant.
 //
-// The category variant lands in Issue #140 (Bilan #2) when the priced-kind
+// Mode = 'account' (Issue #138 / Bilan #1a): create / edit a balance_account
-// switch becomes available. For now this component focuses on creating /
+// row bound to an existing category.
-// editing a `balance_account` record bound to an existing category.
+// Mode = 'category' (Issue #140 / Bilan #2): create a balance_category row
+// with a kind selector (`simple | priced`).
+//
+// Both variants live in the same component because they share the surrounding
+// wiring (form layout, save / cancel buttons, validation feedback) and only
+// the input fields differ.
 
 import { FormEvent, useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
 import type {
   BalanceAccount,
   BalanceCategory,
+  BalanceCategoryKind,
 } from "../../shared/types";
 import type {
   CreateBalanceAccountInput,
+  CreateBalanceCategoryInput,
   UpdateBalanceAccountInput,
 } from "../../services/balance.service";
 
+// -----------------------------------------------------------------------------
+// Account variant types
+// -----------------------------------------------------------------------------
+
 export interface AccountFormValues {
   balance_category_id: number;
   name: string;
@@ -22,7 +33,8 @@ export interface AccountFormValues {
   notes: string;
 }
 
-interface Props {
+interface AccountVariantProps {
+  mode: "account";
   /** When provided, the form is in edit mode; otherwise creation. */
   initialAccount?: BalanceAccount | null;
   categories: BalanceCategory[];
@@ -33,7 +45,26 @@ interface Props {
   onCancel: () => void;
 }
 
-function defaultValues(
+// -----------------------------------------------------------------------------
+// Category variant types (Issue #140)
+// -----------------------------------------------------------------------------
+
+export interface CategoryFormValues {
+  key: string;
+  i18n_key: string;
+  kind: BalanceCategoryKind;
+}
+
+interface CategoryVariantProps {
+  mode: "category";
+  isSaving: boolean;
+  onSubmit: (values: CreateBalanceCategoryInput) => Promise<void> | void;
+  onCancel: () => void;
+}
+
+type Props = AccountVariantProps | CategoryVariantProps;
+
+function defaultAccountValues(
   initial: BalanceAccount | null | undefined,
   categories: BalanceCategory[]
 ): AccountFormValues {
@@ -55,22 +86,33 @@ function defaultValues(
   };
 }
 
-export default function AccountForm({
+export default function AccountForm(props: Props) {
+  if (props.mode === "category") {
+    return <CategoryVariant {...props} />;
+  }
+  return <AccountVariant {...props} />;
+}
+
+// -----------------------------------------------------------------------------
+// Account variant
+// -----------------------------------------------------------------------------
+
+function AccountVariant({
   initialAccount,
   categories,
   isSaving,
   onSubmit,
   onCancel,
-}: Props) {
+}: AccountVariantProps) {
   const { t } = useTranslation();
   const [values, setValues] = useState<AccountFormValues>(() =>
-    defaultValues(initialAccount, categories)
+    defaultAccountValues(initialAccount, categories)
   );
   const [touched, setTouched] = useState(false);
 
   // Reset form when target account changes (edit different row).
   useEffect(() => {
-    setValues(defaultValues(initialAccount, categories));
+    setValues(defaultAccountValues(initialAccount, categories));
     setTouched(false);
   }, [initialAccount, categories]);
 
@@ -80,17 +122,21 @@ export default function AccountForm({
   );
   const isPriced = selectedCategory?.kind === "priced";
   const trimmedName = values.name.trim();
+  const trimmedSymbol = values.symbol.trim();
   const nameInvalid = touched && trimmedName.length === 0;
+  // Priced categories require a symbol — surfaced as a validation error.
+  const symbolMissingForPriced = touched && isPriced && trimmedSymbol.length === 0;
 
   const handleSubmit = async (e: FormEvent) => {
     e.preventDefault();
     setTouched(true);
     if (!trimmedName) return;
+    if (isPriced && !trimmedSymbol) return;
 
     const payload: CreateBalanceAccountInput = {
       balance_category_id: values.balance_category_id,
       name: trimmedName,
-      symbol: values.symbol.trim() || null,
+      symbol: trimmedSymbol || null,
       notes: values.notes.trim() || null,
     };
 
@@ -178,14 +224,24 @@ export default function AccountForm({
           type="text"
           value={values.symbol}
           onChange={(e) => setValues({ ...values, symbol: e.target.value })}
+          onBlur={() => setTouched(true)}
           placeholder={
             isPriced
               ? t("balance.account.form.symbolPlaceholderPriced")
               : t("balance.account.form.symbolPlaceholderSimple")
           }
-          className="w-full px-3 py-2 rounded-lg border border-[var(--border)] bg-[var(--card)] text-sm focus:outline-none focus:ring-1 focus:ring-[var(--primary)]"
+          className={`w-full px-3 py-2 rounded-lg border bg-[var(--card)] text-sm focus:outline-none focus:ring-1 focus:ring-[var(--primary)] ${
+            symbolMissingForPriced
+              ? "border-[var(--negative)]"
+              : "border-[var(--border)]"
+          }`}
           autoComplete="off"
         />
+        {symbolMissingForPriced && (
+          <p className="mt-1 text-xs text-[var(--negative)]">
+            {t("balance.account.form.symbolRequiredForPriced")}
+          </p>
+        )}
       </div>
 
       <div>
@@ -216,7 +272,12 @@ export default function AccountForm({
         </button>
         <button
           type="submit"
-          disabled={isSaving || !trimmedName || categories.length === 0}
+          disabled={
+            isSaving ||
+            !trimmedName ||
+            categories.length === 0 ||
+            (isPriced && !trimmedSymbol)
+          }
           className="px-4 py-2 rounded-lg bg-[var(--primary)] text-white text-sm font-medium hover:opacity-90 disabled:opacity-50"
         >
           {isEditing
@@ -227,3 +288,141 @@ export default function AccountForm({
     </form>
   );
 }
+
+// -----------------------------------------------------------------------------
+// Category variant (Issue #140)
+// -----------------------------------------------------------------------------
+
+function CategoryVariant({
+  isSaving,
+  onSubmit,
+  onCancel,
+}: CategoryVariantProps) {
+  const { t } = useTranslation();
+  const [values, setValues] = useState<CategoryFormValues>({
+    key: "",
+    i18n_key: "",
+    kind: "simple",
+  });
+  const [touched, setTouched] = useState(false);
+
+  const trimmedKey = values.key.trim();
+  const trimmedLabel = values.i18n_key.trim();
+  const keyInvalid = touched && trimmedKey.length === 0;
+
+  const handleSubmit = async (e: FormEvent) => {
+    e.preventDefault();
+    setTouched(true);
+    if (!trimmedKey) return;
+    // Fall back to the key if no human label was supplied.
+    const i18nKey = trimmedLabel || trimmedKey;
+    await onSubmit({
+      key: trimmedKey,
+      i18n_key: i18nKey,
+      kind: values.kind,
+      sort_order: 100, // user-created categories sort after seeded ones
+    });
+  };
+
+  return (
+    <form onSubmit={handleSubmit} className="flex flex-col gap-4">
+      <div className="grid grid-cols-1 sm:grid-cols-2 gap-4">
+        <div>
+          <label
+            className="block text-sm font-medium mb-1"
+            htmlFor="category-key"
+          >
+            {t("balance.category.form.key")}
+          </label>
+          <input
+            id="category-key"
+            type="text"
+            value={values.key}
+            onChange={(e) =>
+              setValues({ ...values, key: e.target.value })
+            }
+            onBlur={() => setTouched(true)}
+            placeholder={t("balance.category.form.keyPlaceholder")}
+            className={`w-full px-3 py-2 rounded-lg border bg-[var(--card)] text-sm focus:outline-none focus:ring-1 focus:ring-[var(--primary)] ${
+              keyInvalid
+                ? "border-[var(--negative)]"
+                : "border-[var(--border)]"
+            }`}
+            autoComplete="off"
+            autoFocus
+          />
+          {keyInvalid && (
+            <p className="mt-1 text-xs text-[var(--negative)]">
+              {t("balance.account.form.nameRequired")}
+            </p>
+          )}
+        </div>
+        <div>
+          <label
+            className="block text-sm font-medium mb-1"
+            htmlFor="category-label"
+          >
+            {t("balance.category.form.label")}
+          </label>
+          <input
+            id="category-label"
+            type="text"
+            value={values.i18n_key}
+            onChange={(e) =>
+              setValues({ ...values, i18n_key: e.target.value })
+            }
+            placeholder={t("balance.category.form.labelPlaceholder")}
+            className="w-full px-3 py-2 rounded-lg border border-[var(--border)] bg-[var(--card)] text-sm focus:outline-none focus:ring-1 focus:ring-[var(--primary)]"
+            autoComplete="off"
+          />
+        </div>
+      </div>
+
+      <div>
+        <label
+          className="block text-sm font-medium mb-1"
+          htmlFor="category-kind"
+        >
+          {t("balance.category.form.kindLabel")}
+        </label>
+        <select
+          id="category-kind"
+          value={values.kind}
+          onChange={(e) =>
+            setValues({
+              ...values,
+              kind: e.target.value as BalanceCategoryKind,
+            })
+          }
+          className="w-full px-3 py-2 rounded-lg border border-[var(--border)] bg-[var(--card)] text-sm focus:outline-none focus:ring-1 focus:ring-[var(--primary)]"
+        >
+          <option value="simple">{t("balance.category.kind.simple")}</option>
+          <option value="priced">{t("balance.category.kind.priced")}</option>
+        </select>
+        <p className="mt-1 text-xs text-[var(--muted-foreground)]">
+          {values.kind === "priced"
+            ? t("balance.category.form.kindHintPriced")
+            : t("balance.category.form.kindHintSimple")}
+        </p>
+      </div>
+
+      <div className="flex justify-end gap-2">
+        <button
+          type="button"
+          onClick={onCancel}
+          disabled={isSaving}
+          className="px-4 py-2 rounded-lg border border-[var(--border)] text-sm hover:bg-[var(--muted)] disabled:opacity-50"
+        >
+          {t("common.cancel")}
+        </button>
+        <button
+          type="submit"
+          disabled={isSaving || !trimmedKey}
+          className="px-4 py-2 rounded-lg bg-[var(--primary)] text-white text-sm font-medium hover:opacity-90 disabled:opacity-50"
+        >
+          {t("balance.category.form.create")}
+        </button>
+      </div>
+    </form>
+  );
+}

src/components/balance/SnapshotEditor.tsx

@@ -1,11 +1,9 @@
 // SnapshotEditor — groups the active accounts by balance category and
 // renders one `SnapshotLineRow` per account.
 //
-// Issue #146 / Bilan #1b: simple-kind editor only. The priced variant
+// Both `simple` and `priced` variants are dispatched by `account.category_kind`
-// (quantity x unit_price + price fetch button) is rendered in #140.
+// inside `SnapshotLineRow`. The editor itself only carries the values down
-// Until then, accounts whose category is `priced` still appear here so
+// and the change handlers up.
-// the user can enter a manual aggregate value — the storage layer accepts
-// a simple-kind line for any account regardless of its category kind.
 
 import { useMemo } from "react";
 import { useTranslation } from "react-i18next";
@@ -13,13 +11,19 @@ import type {
   BalanceAccountWithCategory,
   BalanceCategory,
 } from "../../shared/types";
+import type { PricedEntry } from "../../hooks/useSnapshotEditor";
 import SnapshotLineRow from "./SnapshotLineRow";
 
 interface Props {
   accounts: BalanceAccountWithCategory[];
   categories: BalanceCategory[];
+  /** account_id → string-typed value (simple kind). */
   values: Record<number, string>;
+  /** account_id → {quantity, unit_price} strings (priced kind). */
+  pricedValues: Record<number, PricedEntry>;
   onValueChange: (accountId: number, next: string) => void;
+  onQuantityChange: (accountId: number, next: string) => void;
+  onUnitPriceChange: (accountId: number, next: string) => void;
   disabled?: boolean;
 }
 
@@ -27,7 +31,10 @@ export default function SnapshotEditor({
   accounts,
   categories,
   values,
+  pricedValues,
   onValueChange,
+  onQuantityChange,
+  onUnitPriceChange,
   disabled,
 }: Props) {
   const { t } = useTranslation();
@@ -75,15 +82,22 @@ export default function SnapshotEditor({
             </h3>
           </div>
           <div className="px-4">
-            {catAccounts.map((acc) => (
+            {catAccounts.map((acc) => {
-              <SnapshotLineRow
+              const priced = pricedValues[acc.id];
-                key={acc.id}
+              return (
-                account={acc}
+                <SnapshotLineRow
-                value={values[acc.id] ?? ""}
+                  key={acc.id}
-                onChange={(next) => onValueChange(acc.id, next)}
+                  account={acc}
-                disabled={disabled}
+                  value={values[acc.id] ?? ""}
-              />
+                  quantityValue={priced?.quantity ?? ""}
-            ))}
+                  unitPriceValue={priced?.unit_price ?? ""}
+                  onChange={(next) => onValueChange(acc.id, next)}
+                  onQuantityChange={(next) => onQuantityChange(acc.id, next)}
+                  onUnitPriceChange={(next) => onUnitPriceChange(acc.id, next)}
+                  disabled={disabled}
+                />
+              );
+            })}
           </div>
         </div>
       ))}

src/components/balance/SnapshotLineRow.tsx

@@ -1,23 +1,53 @@
 // SnapshotLineRow — single account line inside the snapshot editor.
 //
-// Issue #146 / Bilan #1b ships the *simple* variant only: a single value
+// Two variants are dispatched by `account.category_kind`:
-// input keyed by `account_id`. The priced variant (quantity / unit_price /
-// computed value + price-fetch button) lands in Issue #140 / Bilan #2.
 //
-// We intentionally keep this component dumb: it receives a string value
+//  - `simple`  (Issue #146): a single value input keyed by `account_id`.
-// from the parent (the editor stores raw strings to preserve partial input
+//  - `priced`  (Issue #140): three inputs — `quantity`, `unit_price` (both
-// the user is typing) and emits the new string on every change. Numeric
+//                            required), and a read-only `value` field that
-// validation happens at save time in `useSnapshotEditor.save`.
+//                            renders `quantity * unit_price` live as the
+//                            user types. An attribution tag `[Manuel]`
+//                            appears next to the row; the `[via Maximus]`
+//                            tag will land with Issue #143 (price-fetching).
+//
+// We keep this component dumb on purpose: it receives strings from the
+// parent (the editor stores raw strings to preserve partial input) and
+// emits new strings on every change. Numeric validation happens at save
+// time in `useSnapshotEditor.save` against the service's
+// `validateLineKindInvariants` helper.
 
-import { ChangeEvent } from "react";
+import { ChangeEvent, useMemo } from "react";
 import { useTranslation } from "react-i18next";
 import type { BalanceAccountWithCategory } from "../../shared/types";
 
-interface Props {
+interface BaseProps {
   account: BalanceAccountWithCategory;
+  disabled?: boolean;
+}
+
+interface SimpleProps extends BaseProps {
   value: string;
   onChange: (next: string) => void;
-  disabled?: boolean;
+  /** Optional priced handlers for callers that wire both at once. */
+  quantityValue?: string;
+  unitPriceValue?: string;
+  onQuantityChange?: (next: string) => void;
+  onUnitPriceChange?: (next: string) => void;
+}
+
+type Props = SimpleProps;
+
+/**
+ * Parse a string like "12.34" or "12,34" into a finite number, or null
+ * if invalid / empty. Used by the priced variant to compute the live
+ * `value` preview.
+ */
+function parseDecimal(raw: string): number | null {
+  if (!raw) return null;
+  const trimmed = String(raw).trim().replace(",", ".");
+  if (!trimmed) return null;
+  const n = Number(trimmed);
+  return Number.isFinite(n) ? n : null;
 }
 
 export default function SnapshotLineRow({
@@ -25,9 +55,119 @@ export default function SnapshotLineRow({
   value,
   onChange,
   disabled,
+  quantityValue,
+  unitPriceValue,
+  onQuantityChange,
+  onUnitPriceChange,
 }: Props) {
   const { t } = useTranslation();
+  const isPriced = account.category_kind === "priced";
 
+  // Compute the live value preview for priced rows. Returns null when
+  // either input cannot yet be parsed (so we display a placeholder).
+  const computedPricedValue = useMemo(() => {
+    if (!isPriced) return null;
+    const qty = parseDecimal(quantityValue ?? "");
+    const price = parseDecimal(unitPriceValue ?? "");
+    if (qty === null || price === null) return null;
+    return qty * price;
+  }, [isPriced, quantityValue, unitPriceValue]);
+
+  if (isPriced) {
+    const handleQty = (e: ChangeEvent<HTMLInputElement>) =>
+      onQuantityChange?.(e.target.value);
+    const handlePrice = (e: ChangeEvent<HTMLInputElement>) =>
+      onUnitPriceChange?.(e.target.value);
+
+    return (
+      <div className="flex flex-col sm:flex-row sm:items-center gap-3 py-2 border-b border-[var(--border)] last:border-b-0">
+        <div className="flex-1 min-w-0">
+          <div className="flex items-center gap-2">
+            <span className="text-sm font-medium truncate">{account.name}</span>
+            <span
+              className="text-[10px] uppercase tracking-wide px-1.5 py-0.5 rounded bg-[var(--muted)] text-[var(--muted-foreground)]"
+              title={t("balance.snapshot.priced.attributionManualHint")}
+            >
+              {t("balance.snapshot.priced.attributionManual")}
+            </span>
+          </div>
+          {account.symbol && (
+            <div className="text-xs text-[var(--muted-foreground)]">
+              {account.symbol}
+            </div>
+          )}
+        </div>
+        <div className="flex flex-wrap items-center gap-2">
+          <div className="flex flex-col gap-0.5">
+            <input
+              type="text"
+              inputMode="decimal"
+              value={quantityValue ?? ""}
+              onChange={handleQty}
+              disabled={disabled}
+              placeholder={t("balance.snapshot.priced.quantityPlaceholder")}
+              className="w-24 px-3 py-2 rounded-lg border border-[var(--border)] bg-[var(--card)] text-sm text-right focus:outline-none focus:ring-1 focus:ring-[var(--primary)] disabled:opacity-50"
+              aria-label={t("balance.snapshot.priced.quantityLabel", {
+                account: account.name,
+              })}
+            />
+            <span className="text-[10px] text-[var(--muted-foreground)] text-right">
+              {t("balance.snapshot.priced.quantity")}
+            </span>
+          </div>
+          <span className="text-sm text-[var(--muted-foreground)] hidden sm:inline">
+            ×
+          </span>
+          <div className="flex flex-col gap-0.5">
+            <input
+              type="text"
+              inputMode="decimal"
+              value={unitPriceValue ?? ""}
+              onChange={handlePrice}
+              disabled={disabled}
+              placeholder={t("balance.snapshot.priced.unitPricePlaceholder")}
+              className="w-28 px-3 py-2 rounded-lg border border-[var(--border)] bg-[var(--card)] text-sm text-right focus:outline-none focus:ring-1 focus:ring-[var(--primary)] disabled:opacity-50"
+              aria-label={t("balance.snapshot.priced.unitPriceLabel", {
+                account: account.name,
+              })}
+            />
+            <span className="text-[10px] text-[var(--muted-foreground)] text-right">
+              {t("balance.snapshot.priced.unitPrice")}
+            </span>
+          </div>
+          <span className="text-sm text-[var(--muted-foreground)] hidden sm:inline">
+            =
+          </span>
+          <div className="flex flex-col gap-0.5">
+            <input
+              type="text"
+              value={
+                computedPricedValue === null
+                  ? ""
+                  : computedPricedValue.toFixed(2)
+              }
+              readOnly
+              disabled
+              placeholder={t("balance.snapshot.priced.computedValuePlaceholder")}
+              className="w-32 px-3 py-2 rounded-lg border border-[var(--border)] bg-[var(--muted)]/40 text-sm text-right text-[var(--muted-foreground)] focus:outline-none cursor-not-allowed"
+              aria-label={t("balance.snapshot.priced.computedValueLabel", {
+                account: account.name,
+              })}
+              aria-readonly="true"
+            />
+            <span className="text-[10px] text-[var(--muted-foreground)] text-right">
+              {t("balance.snapshot.priced.computedValue")}
+            </span>
+          </div>
+          <span className="text-xs text-[var(--muted-foreground)] w-10">
+            {account.currency}
+          </span>
+        </div>
+      </div>
+    );
+  }
+
+  // Simple variant — unchanged from #146.
   const handleChange = (e: ChangeEvent<HTMLInputElement>) => {
     onChange(e.target.value);
   };

src/hooks/useSnapshotEditor.ts

@@ -38,6 +38,12 @@ import {
 
 export type SnapshotEditorMode = "new" | "edit";
 
+/** String-typed entry for a priced-kind line being edited. */
+export interface PricedEntry {
+  quantity: string;
+  unit_price: string;
+}
+
 interface State {
   mode: SnapshotEditorMode;
   /** ISO YYYY-MM-DD; controlled in 'new' mode, frozen in 'edit'. */
@@ -49,11 +55,16 @@ interface State {
   /** Used to group lines by category in the editor view. */
   categories: BalanceCategory[];
   /**
-   * Map of account_id → string-typed value. We keep strings to preserve
+   * Map of account_id → string-typed value (simple kind only). We keep
-   * empty / partial input the user is typing; conversion to number happens
+   * strings to preserve empty / partial input; conversion to number
-   * at save time (and at validation when needed).
+   * happens at save time.
    */
   values: Record<number, string>;
+  /**
+   * Map of account_id → string-typed `{quantity, unit_price}` (priced
+   * kind only). Same partial-input guarantee as `values`.
+   */
+  pricedValues: Record<number, PricedEntry>;
   /** Snapshot whose values would prefill if the user clicks "Prefill". */
   previousSnapshot: BalanceSnapshot | null;
   /** Lines from `previousSnapshot` (loaded lazily when needed). */
@@ -78,13 +89,28 @@ type Action =
         accounts: BalanceAccountWithCategory[];
         categories: BalanceCategory[];
         values: Record<number, string>;
+        pricedValues: Record<number, PricedEntry>;
         previousSnapshot: BalanceSnapshot | null;
         previousLines: BalanceSnapshotLine[] | null;
       };
     }
   | { type: "SET_DATE"; payload: string }
   | { type: "SET_VALUE"; payload: { accountId: number; value: string } }
-  | { type: "PREFILL"; payload: Record<number, string> }
+  | {
+      type: "SET_PRICED_FIELD";
+      payload: {
+        accountId: number;
+        field: "quantity" | "unit_price";
+        value: string;
+      };
+    }
+  | {
+      type: "PREFILL";
+      payload: {
+        values: Record<number, string>;
+        pricedValues: Record<number, PricedEntry>;
+      };
+    }
   | { type: "RESET" }
   | { type: "CLEAR_DIRTY" };
 
@@ -96,6 +122,7 @@ function initialState(initialDate: string): State {
     accounts: [],
     categories: [],
     values: {},
+    pricedValues: {},
     previousSnapshot: null,
     previousLines: null,
     isLoading: false,
@@ -129,6 +156,7 @@ function reducer(state: State, action: Action): State {
         accounts: action.payload.accounts,
         categories: action.payload.categories,
         values: action.payload.values,
+        pricedValues: action.payload.pricedValues,
         previousSnapshot: action.payload.previousSnapshot,
         previousLines: action.payload.previousLines,
         isLoading: false,
@@ -148,10 +176,33 @@ function reducer(state: State, action: Action): State {
         },
         isDirty: true,
       };
+    case "SET_PRICED_FIELD": {
+      const existing =
+        state.pricedValues[action.payload.accountId] ?? {
+          quantity: "",
+          unit_price: "",
+        };
+      const next: PricedEntry =
+        action.payload.field === "quantity"
+          ? { ...existing, quantity: action.payload.value }
+          : { ...existing, unit_price: action.payload.value };
+      return {
+        ...state,
+        pricedValues: {
+          ...state.pricedValues,
+          [action.payload.accountId]: next,
+        },
+        isDirty: true,
+      };
+    }
     case "PREFILL":
       return {
         ...state,
-        values: { ...state.values, ...action.payload },
+        values: { ...state.values, ...action.payload.values },
+        pricedValues: {
+          ...state.pricedValues,
+          ...action.payload.pricedValues,
+        },
         isDirty: true,
       };
     case "RESET":
@@ -160,6 +211,7 @@ function reducer(state: State, action: Action): State {
         // Keep the loaded structure (accounts, categories, snapshot) but wipe
         // user input back to a clean slate sourced from the saved lines.
         values: {},
+        pricedValues: {},
         isDirty: true,
       };
     case "CLEAR_DIRTY":
@@ -222,11 +274,37 @@ export function useSnapshotEditor(options: Options = {}) {
       const existing = await getSnapshotByDate(targetDate);
       const isEdit = !!existing;
       let values: Record<number, string> = {};
+      let pricedValues: Record<number, PricedEntry> = {};
       let previousLines: BalanceSnapshotLine[] | null = null;
+      // Index account kinds for quick line classification.
+      const kindByAccountId = new Map<number, BalanceCategory["kind"]>();
+      for (const acc of accounts) {
+        kindByAccountId.set(acc.id, acc.category_kind);
+      }
       if (existing) {
         const lines = await listLinesBySnapshot(existing.id);
         for (const line of lines) {
-          values[line.account_id] = String(line.value);
+          // The line itself carries quantity / unit_price for priced kinds;
+          // we still cross-check against the account kind to decide which
+          // input map this row belongs to (it dictates what the user sees).
+          const kind = kindByAccountId.get(line.account_id);
+          if (
+            kind === "priced" ||
+            (line.quantity !== null && line.unit_price !== null)
+          ) {
+            pricedValues[line.account_id] = {
+              quantity:
+                line.quantity !== null && line.quantity !== undefined
+                  ? String(line.quantity)
+                  : "",
+              unit_price:
+                line.unit_price !== null && line.unit_price !== undefined
+                  ? String(line.unit_price)
+                  : "",
+            };
+          } else {
+            values[line.account_id] = String(line.value);
+          }
         }
       }
       const previous = await getPreviousSnapshot(targetDate);
@@ -243,6 +321,7 @@ export function useSnapshotEditor(options: Options = {}) {
           accounts,
           categories,
           values,
+          pricedValues,
           previousSnapshot: previous,
           previousLines,
         },
@@ -269,17 +348,36 @@ export function useSnapshotEditor(options: Options = {}) {
     });
   }, []);
 
+  const setLineQuantity = useCallback(
+    (accountId: number, value: string) => {
+      dispatch({
+        type: "SET_PRICED_FIELD",
+        payload: { accountId, field: "quantity", value },
+      });
+    },
+    []
+  );
+
+  const setLineUnitPrice = useCallback(
+    (accountId: number, value: string) => {
+      dispatch({
+        type: "SET_PRICED_FIELD",
+        payload: { accountId, field: "unit_price", value },
+      });
+    },
+    []
+  );
+
   const reset = useCallback(() => {
     dispatch({ type: "RESET" });
   }, []);
 
   /**
    * Build the prefill map from the previous snapshot. Per spec-decisions
-   * row "Bouton Pré-remplir" (Issue 1b decision):
+   * row "Bouton Pré-remplir":
    *   - simple kind  → copy value
-   *   - priced kind  → copy quantity, leave unit_price blank → effectively
+   *   - priced kind  → copy quantity, leave unit_price blank (the user
-   *                    no-op at Issue #146 because priced UI ships in #140.
+   *                    must enter or fetch a fresh price each time).
-   *                    We add a TODO so the priced branch is explicit.
    */
   const prefillFromPrevious = useCallback(() => {
     const lines = state.previousLines;
@@ -288,18 +386,29 @@ export function useSnapshotEditor(options: Options = {}) {
     for (const acc of state.accounts) {
       accountKindById.set(acc.id, acc.category_kind);
     }
-    const next: Record<number, string> = {};
+    const nextSimple: Record<number, string> = {};
+    const nextPriced: Record<number, PricedEntry> = {};
     for (const line of lines) {
       const kind = accountKindById.get(line.account_id);
       if (!kind) continue; // archived account — skip
       if (kind === "simple") {
-        next[line.account_id] = String(line.value);
+        nextSimple[line.account_id] = String(line.value);
       } else {
-        // TODO Issue #140 — implement priced prefill (quantity copy, leave
+        // Priced: copy quantity, leave unit_price blank — quantities don't
-        // unit_price blank). For Issue #146 the priced UI does not exist yet.
+        // change unless the user buys / sells, prices always change.
+        nextPriced[line.account_id] = {
+          quantity:
+            line.quantity !== null && line.quantity !== undefined
+              ? String(line.quantity)
+              : "",
+          unit_price: "",
+        };
       }
     }
-    dispatch({ type: "PREFILL", payload: next });
+    dispatch({
+      type: "PREFILL",
+      payload: { values: nextSimple, pricedValues: nextPriced },
+    });
   }, [state.previousLines, state.accounts]);
 
   /**
@@ -326,7 +435,13 @@ export function useSnapshotEditor(options: Options = {}) {
           snapshot_date: state.snapshotDate,
         });
       }
-      const lines = Object.entries(state.values)
+      // Index account kinds for line classification at save time.
+      const kindByAccountId = new Map<number, BalanceCategory["kind"]>();
+      for (const acc of state.accounts) {
+        kindByAccountId.set(acc.id, acc.category_kind);
+      }
+      // Simple-kind lines: drop empty fields, accept any finite number.
+      const simpleLines = Object.entries(state.values)
         .filter(([, v]) => v !== undefined && String(v).trim().length > 0)
         .map(([accountIdStr, raw]) => {
           const accountId = Number(accountIdStr);
@@ -338,9 +453,49 @@ export function useSnapshotEditor(options: Options = {}) {
               `Invalid value for account ${accountId}: "${raw}"`
             );
           }
-          return { account_id: accountId, value: num };
+          return {
+            account_id: accountId,
+            value: num,
+            account_kind: "simple" as const,
+          };
         });
-      await upsertSnapshotLines(snapshotId, lines);
+      // Priced-kind lines: both qty + price required, value computed.
+      const pricedLines = Object.entries(state.pricedValues)
+        .filter(
+          ([, entry]) =>
+            entry &&
+            String(entry.quantity ?? "").trim().length > 0 &&
+            String(entry.unit_price ?? "").trim().length > 0
+        )
+        .map(([accountIdStr, entry]) => {
+          const accountId = Number(accountIdStr);
+          const qtyTrim = String(entry.quantity).trim().replace(",", ".");
+          const priceTrim = String(entry.unit_price).trim().replace(",", ".");
+          const qty = Number(qtyTrim);
+          const price = Number(priceTrim);
+          if (!Number.isFinite(qty)) {
+            throw new BalanceServiceError(
+              "snapshot_priced_quantity_required",
+              `Invalid quantity for account ${accountId}: "${entry.quantity}"`
+            );
+          }
+          if (!Number.isFinite(price)) {
+            throw new BalanceServiceError(
+              "snapshot_priced_unit_price_required",
+              `Invalid unit_price for account ${accountId}: "${entry.unit_price}"`
+            );
+          }
+          return {
+            account_id: accountId,
+            account_kind: "priced" as const,
+            quantity: qty,
+            unit_price: price,
+            // value = qty * price; the service re-validates the relation
+            // within PRICED_VALUE_TOLERANCE before persisting.
+            value: qty * price,
+          };
+        });
+      await upsertSnapshotLines(snapshotId, [...simpleLines, ...pricedLines]);
       dispatch({ type: "CLEAR_DIRTY" });
       // Reload so 'new' mode flips to 'edit' and the snapshot row is in state.
       await loadForDate(state.snapshotDate);
@@ -356,6 +511,8 @@ export function useSnapshotEditor(options: Options = {}) {
     state.snapshot,
     state.snapshotDate,
     state.values,
+    state.pricedValues,
+    state.accounts,
     loadForDate,
   ]);
 
@@ -377,6 +534,8 @@ export function useSnapshotEditor(options: Options = {}) {
     state,
     setDate,
     setLineValue,
+    setLineQuantity,
+    setLineUnitPrice,
     reset,
     prefillFromPrevious,
     save,

src/pages/SnapshotEditPage.tsx

@@ -49,7 +49,8 @@ export default function SnapshotEditPage() {
   const isEditMode = state.mode === "edit";
   const canPrefill = !!state.previousSnapshot;
 
-  // Aggregate value (simple kind only — sums all visible numeric inputs).
+  // Aggregate value across simple + priced lines (computed live as the
+  // user types). Priced contribution = quantity × unit_price.
   const totalValue = useMemo(() => {
     let total = 0;
     let hasAny = false;
@@ -62,8 +63,19 @@ export default function SnapshotEditPage() {
         hasAny = true;
       }
     }
+    for (const entry of Object.values(state.pricedValues)) {
+      if (!entry) continue;
+      const qty = Number(String(entry.quantity ?? "").trim().replace(",", "."));
+      const price = Number(
+        String(entry.unit_price ?? "").trim().replace(",", ".")
+      );
+      if (Number.isFinite(qty) && Number.isFinite(price)) {
+        total += qty * price;
+        hasAny = true;
+      }
+    }
     return hasAny ? total : null;
-  }, [state.values]);
+  }, [state.values, state.pricedValues]);
 
   const handleSave = async () => {
     try {
@@ -184,7 +196,10 @@ export default function SnapshotEditPage() {
           accounts={state.accounts}
           categories={state.categories}
           values={state.values}
+          pricedValues={state.pricedValues}
           onValueChange={editor.setLineValue}
+          onQuantityChange={editor.setLineQuantity}
+          onUnitPriceChange={editor.setLineUnitPrice}
           disabled={state.isSaving}
         />
       )}