Standards-unification batch 1 (CODE_STANDARDS 'Error responses', exemplar
categories.cts): inline res.status().json(standardizeError(...)) bodies and
try/catch-500 wrappers replaced with thrown ApiError factories; the terminal
handler formats 4xx and masks+logs 5xx. Wire shapes preserved, including
client-visible codes (ALREADY_MATCHED, DUPLICATE_MATCH, NOT_MATCHED,
NO_DEBTS, INVALID_PLAN_STATE, BANK_SYNC_DISABLED).
Also kills three more err.message-on-500 leaks in dataSources.cts (DB_ERROR
wrappers) that the QA-B13-02 grep missed; SimpleFIN errors keep their
deliberate sanitized pass-through via ApiError wraps (tokens/URLs stripped).
snowballPlanRoute.test.js harness now mirrors the terminal handler for
thrown errors (same wire shape as production). Server suite 252/252.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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