feat: unified document inbox, full BAS 2026, and document-transaction matching

- Expand BAS reference from ~180 to ~1,276 accounts (full BAS Kontoplan 2026)
  with K2 exclusion flags, per-class data files, and computed SRU codes
- Evolve invoice inbox into unified document inbox handling invoices, receipts,
  and government letters with AI-powered classification (Claude Haiku Vision)
- Add multi-pass document-to-transaction matching engine with greedy assignment
  for both supplier invoices (reference/amount/date/name) and receipts
  (weighted amount/merchant/date scoring)
- Add supplier invoice matching in transaction ingest pipeline
- Inject booking template suggestions into AI extraction prompts
- Surface matched documents in swipe categorization UI with one-tap booking
- Auto-activate missing BAS accounts during SIE import against full reference
- Add K2 filter toggle in Chart of Accounts manager
- Add receipt confirmation route with BFNAR representation fields
- Add database migrations for K2 support and document matching columns
- Remove obsolete extension migration scripts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/api/schemas.ts

@@ -311,6 +311,7 @@ export const CategorizeTransactionSchema = z.object({
   vat_treatment: VatTreatmentSchema.optional(),
   account_override: accountNumber.optional(),
   user_description: z.string().max(500).optional(),
+  inbox_item_id: z.string().uuid().optional(),
 })
 
 export const BookTransactionSchema = z.object({