Add four service helpers used by the upcoming `/balance` overview:
- getSnapshotTotalsByDate(range?) — SUM(value) GROUP BY snapshot_date
with an optional inclusive [from, to] range. LEFT JOIN preserves
empty snapshots as zero rows so the chart shows continuity.
- getSnapshotTotalsByCategoryAndDate(range?) — same aggregation broken
down by balance_categories.key, returned as one row per snapshot
date with a `byCategory` map. Powers the stacked-area variant.
- getAccountsLatestSnapshot() — one row per active account with the
value of its most-recent snapshot line (NULL when none exists).
Filters archived accounts via WHERE is_active = 1 AND archived_at
IS NULL, matches the listBalanceAccounts default.
- getAccountsPeriodAnchor(range) — earliest snapshot_date >= from
per account, with the value at that date — the anchor used to
compute the per-account Δ% column on the accounts table.
Tests cover empty DB, single/multi snapshot, archived exclusion via
SQL inspection, date-range params (from-only, both bounds, open).
Refs: #141
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the snapshots + lines section of the balance service for Issue #146
(Bilan #1b). Simple-kind only — quantity / unit_price are forced to NULL
both at the SQL CHECK level (already in v9) and at the service level
(`upsertSnapshotLines` validates ahead of time). Priced-kind upsert lands
in #140.
New service exports:
- listSnapshots / getSnapshotByDate / getSnapshotById / getPreviousSnapshot
- createSnapshot (throws snapshot_date_taken when UNIQUE per date violated
so the UI can redirect to edit mode)
- updateSnapshot / deleteSnapshot (cascade lines via FK)
- listLinesBySnapshot / upsertSnapshotLines (rewrite-all strategy)
New BalanceErrorCode entries: snapshot_date_required, snapshot_date_taken,
snapshot_not_found, snapshot_value_invalid, snapshot_priced_unsupported.
New shared types: BalanceSnapshot, BalanceSnapshotLine.
22 new vitest cases cover: invalid-date guards, unique-per-date violation,
simple-kind null invariant on inserts, NaN/Infinity rejection,
clear+rewrite line semantics, getPreviousSnapshot strict-before ordering.
Refs #146
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
