feat: conceptos tab, filters, backfill, facturapi live keys, fixes

- Add Conceptos tab in CFDI page with column filters, sorting, pagination
- Add GET /cfdi/conceptos endpoint with filters and orderBy
- Backfill cfdi_conceptos from legacy XMLs (824k concepts inserted)
- Fix CFDI delete button (bypass subscription check, add alerts)
- Fix export to Excel (fetch all filtered results, limit 10k)
- Fix facturacion page concepto delete bug (immutable updates, unique ids)
- Add Facturapi live key auto-generation and caching
- Fix SAT fechaPagoP parsing
- Add metrics cache support for current year
- Increase DB pool max to 15

apps/api/src/config/env.ts

@@ -38,6 +38,7 @@ const envSchema = z.object({
 
   // Facturapi
   FACTURAPI_USER_KEY: z.string().optional(),
+  FACTURAPI_MODE: z.enum(['test', 'live']).optional(),
 
   // Cloudflare Tunnel (connector BYO-DB)
   CLOUDFLARE_API_TOKEN: z.string().optional(),