- Cleans expired verifications and orphaned usage rows
- Previously only ran once on startup (13d+ uptime = accumulation)
- Interval uses .unref() to not block graceful shutdown
- Stopped during shutdown before pool.end()
- Idempotent start (safe to call multiple times)
- 6 TDD tests added (periodic-cleanup.test.ts)
- 663 tests total, all passing
- New src/utils/pdf-handler.ts with handlePdfRoute() helper
- Handles: content-type validation, PDF option validation, slot acquire/release, error mapping, response headers
- Refactored convert.ts from 388 to 233 lines (40% reduction)
- 10 TDD tests for the new helper (RED→GREEN verified)
- All 618 tests passing, zero tsc --noEmit errors
- Replace all catch(err: any) with catch(err: unknown) across 8 source files
- Add errorMessage() and errorCode() helpers for safe error property access
- Type nodemailer transport config as SMTPTransport.Options (was any)
- Type health endpoint databaseStatus (was any)
- Type convert route margin param (was any)
- Change queryWithRetry params from any[] to unknown[]
- Update isTransientError to require Error instances (was accepting plain objects)
- 19 new TDD tests (error-type-safety.test.ts)
- Updated existing tests to use proper Error instances
- 598 tests total, all passing, zero type errors
