refactor(gating): one constant for the split's feature key

Review of PR #452 (comment 24129): "adjustments" was written three
times for the split (the page's gate, the button's edition, the
dialog's locked screen). SPLIT_FEATURE in splitGate.ts is now the one
source, so moving the split to its own key or to Premium is a one-line
change. No behaviour change; setting it to "budget" turns 2 tests red.

Refs #369

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/components/transactions/SplitButton.tsx

@@ -2,7 +2,7 @@ import { useTranslation } from "react-i18next";
 import { Lock, Split } from "lucide-react";
 import type { TransactionRow } from "../../shared/types";
 import { requiredTierFor } from "../../shared/entitlements";
-import type { SplitAccess } from "../../shared/splitGate";
+import { SPLIT_FEATURE, type SplitAccess } from "../../shared/splitGate";
 
 interface SplitButtonProps {
   row: TransactionRow;
@@ -40,7 +40,7 @@ export default function SplitButton({ row, access, onOpenSplit, onOpenUpsell }:
       title={
         locked
           ? t("transactions.splitLocked", {
-              tier: t(`license.editions.${requiredTierFor("adjustments")}`),
+              tier: t(`license.editions.${requiredTierFor(SPLIT_FEATURE)}`),
             })
           : t("transactions.splitAdjustment")
       }

src/components/transactions/TransactionTable.tsx

@@ -8,7 +8,7 @@ import type {
   SplitChild,
 } from "../../shared/types";
 import type { LinkedTransferTooltipRow } from "../../services/balance.service";
-import type { SplitAccess } from "../../shared/splitGate";
+import { SPLIT_FEATURE, type SplitAccess } from "../../shared/splitGate";
 import { onboardingTargetAttributes } from "../../utils/onboardingPath";
 import CategoryCombobox from "../shared/CategoryCombobox";
 import UpsellDialog from "../shared/UpsellDialog";
@@ -28,7 +28,7 @@ interface TransactionTableProps {
   onDeleteSplit: (parentId: number) => Promise<void>;
   /**
    * What the Répartition button does (#369): `splitAccessFor` over
-   * `useEntitlement("adjustments")`. Required on purpose: a default of "open"
+   * `useEntitlement(SPLIT_FEATURE)`. Required on purpose: a default of "open"
    * would let a new caller leave the split ungated without a word.
    */
   splitAccess: SplitAccess;
@@ -351,7 +351,7 @@ export default function TransactionTable({
       )}
       {/* Symmetric: the upsell goes away once the edition resolves to Base or Premium. */}
       {showSplitUpsell && splitAccess !== "open" && (
-        <UpsellDialog feature="adjustments" onClose={() => setShowSplitUpsell(false)} />
+        <UpsellDialog feature={SPLIT_FEATURE} onClose={() => setShowSplitUpsell(false)} />
       )}
     </div>
   );

src/pages/TransactionsPage.tsx

@@ -7,7 +7,7 @@ import EmptyState from "../components/shared/EmptyState";
 import OnboardingStepCard from "../components/onboarding/OnboardingStepCard";
 import { useOnboarding } from "../contexts/OnboardingContext";
 import { useEntitlement } from "../hooks/useEntitlement";
-import { splitAccessFor } from "../shared/splitGate";
+import { SPLIT_FEATURE, splitAccessFor } from "../shared/splitGate";
 import {
   readOnboardingNavState,
   showsStepCard,
@@ -44,7 +44,7 @@ export default function TransactionsPage() {
   const onboarding = useOnboarding();
   // The Répartition button belongs to the Base edition (#369): locked with the
   // upsell on Free, inert while the license is not ready. The page itself stays Free.
-  const splitGate = useEntitlement("adjustments");
+  const splitGate = useEntitlement(SPLIT_FEATURE);
   const [resultMessage, setResultMessage] = useState<string | null>(null);
   const [menu, setMenu] = useState<{ x: number; y: number; row: TransactionRow } | null>(null);
   const [pending, setPending] = useState<TransactionRow | null>(null);

src/shared/splitGate.ts

@@ -19,11 +19,19 @@
  * license refresh — never locked, never open on a fail-closed `allowed`.
  */
 import type { EntitlementGate } from "./profileGate";
+import type { FeatureKey } from "./entitlements";
+
+/**
+ * The feature the split belongs to. The page reads its gate, the button names
+ * its edition and the dialog shows its locked screen from this one constant, so
+ * moving the split (to its own key, to Premium) is a one-line change.
+ */
+export const SPLIT_FEATURE: FeatureKey = "adjustments";
 
 /** What the split button does: open the split window, show the upsell, or nothing yet. */
 export type SplitAccess = "open" | "locked" | "pending";
 
-/** The split button's access, from the gate `useEntitlement("adjustments")` returns. */
+/** The split button's access, from the gate `useEntitlement(SPLIT_FEATURE)` returns. */
 export function splitAccessFor(gate: EntitlementGate): SplitAccess {
   if (!gate.ready) return "pending";
   return gate.allowed ? "open" : "locked";