- Create src/web/src/lib/formatters.ts with all exports from both modules
- Migrate all 14 import sites to @/lib/formatters (Opción A — immediate migration)
- Replace dateFormat.test.ts with formatters.test.ts including 10 smoke tests + full suite
- Delete src/web/src/lib/dateFormat.ts and numberFormat.ts
- 464 tests green, tsc clean (TS5101 warning is pre-existing)