intake: POST /api/intake router + PUT /api/transactions/[id]/line-items (plan §11 C1, C2)

One upload point, every applicable step. Persist the batch, classify each
file, ONE LiteLLM call (cloud-budget, temperature 0, strict json_schema; PDFs
as unpdf text, never pixels) with an order-item prompt that keeps names
verbatim, header (merchant, date, total), merchant pattern
(coles|woolworths|woolies|aldi|iga|foodworks|costco) -> grocery | food | ask,
exact (platform, merchant, date, total) match against transactions +
expense_metadata, then act:

- food + unique match  -> replace line_items via the C2 path, 'enriched'
- food + miss/ambiguity -> 'candidates' (same merchant ±3d) with
  intake_use_candidate / intake_create buttons; never auto-creates
- grocery              -> original files to pantry POST /api/capture with
  finance_target_transaction_id + finance_action enrich|create (C3);
  409 -> 'duplicate'
- ask / needs_header / held / duplicate / unsupported as replies, not writes

Reconciliation is against the printed item subtotal (a delivery total is
items + fees - promotions: 18.94 of Coles lines settled at 5.74),  or
2%, else 'held'. Originals are kept under INTAKE_FILE_DIR by sha256 so a later
'Groceries' tap can still forward them.

C2 is an idempotent replace on transaction_id = :id OR
matched_transaction_id = :id, accepts INTAKE_TOKEN or RECEIPT_INGEST_TOKEN,
creates the expense_metadata row when absent, 404 when the transaction does
not exist, returns {previous_line_items, line_items} so pantry's undo is the
same call with the previous list.

package.json

@@ -23,7 +23,8 @@
     "prisma": "^7.4.2",
     "react": "19.2.3",
     "react-dom": "19.2.3",
-    "recharts": "^3.8.0"
+    "recharts": "^3.8.0",
+    "unpdf": "^1.8.1"
   },
   "devDependencies": {
     "@tailwindcss/postcss": "^4",