- formatError() now emits `code` (the field the client reads) and hides
internals on any 5xx (missing status treated as 500). Single body shape
everywhere: { error, message, code, field? }.
- The terminal error handler now delegates to formatError, so a thrown
ApiError produces its real status + message + code (previously every
error collapsed to a generic "Internal server error"). Only 5xx are
logged/recorded; 4xx client errors no longer spam the error tracker.
This unblocks the Express-5 `throw ApiError` route pattern.
- Resilience: added `uncaughtException` (record + exit for clean restart),
enriched `unhandledRejection` (record, don't crash), and a SIGTERM/SIGINT
graceful shutdown that drains connections, checkpoints the WAL, and
closes the DB — verified: kill -TERM → "database closed cleanly" + exit.
check:server + typecheck:server clean; 232/232 tests.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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