wip(intake): router, enrich endpoint, Slack handlers, migration 0034 — UNTESTED checkpoint

Agent was terminated by the session usage limit before running lint/tests or
writing its report. Files are complete drafts against plan §11 (C1, C2, C5):
src/app/api/intake/, src/app/api/transactions/[id]/line-items/, src/lib/intake-*.ts,
src/lib/line-items.ts, prisma/migrations/0034_intake_batches, fixtures + tests.
Next: npm ci && npx prisma generate && npm run lint && npm test && npm run test:integration.

prisma/migrations/0034_intake_batches/migration.sql

@@ -0,0 +1,64 @@
+-- Intake router (plans/intake-router-slice-plan.md §11 C1, smarthome repo).
+--
+-- One upload point for receipts — a screenshot, a PDF export, a pasted body —
+-- that reads what it was given and does every step that applies: fill the
+-- empty `line_items` on the order the email pipeline already booked, hand a
+-- grocery receipt to pantry, or ask when it cannot tell.
+--
+-- Every batch is persisted BEFORE anything is extracted, for two reasons:
+--   1. The Slack card it produces carries buttons ("Use this", "Create",
+--      "Groceries or a meal?") that are pressed minutes later in a fresh
+--      request with nothing but the batch id to go on.
+--   2. A re-share of an already-handled order — a second crop, the PDF after
+--      the screenshot — must be recognised, and the only durable evidence of
+--      the first share is this row (`file_sha256` overlap, or the same
+--      (platform, merchant, date, total) header already resolved).
+--
+-- `id` is the uuid n8n mints per webhook call, so a retried delivery is the
+-- same batch rather than a second one. `header` holds the extracted
+-- (merchant, order_date, total, platform, ...) and `items` the verbatim item
+-- list, so a later tap can enrich or create without re-reading the files.
+--
+-- Idempotent: safe to re-run.
+
+CREATE TABLE IF NOT EXISTS intake_batches (
+  id             uuid PRIMARY KEY,
+  source         text NOT NULL,
+  shared_by      text,
+  file_sha256    text[] NOT NULL DEFAULT '{}',
+  header         jsonb,
+  items          jsonb,
+  kind           text,
+  status         text NOT NULL,
+  transaction_id integer,
+  capture_id     integer,
+  created_at     timestamptz NOT NULL DEFAULT now(),
+  resolved_at    timestamptz
+);
+
+COMMENT ON TABLE intake_batches IS
+  'One row per upload batch through POST /api/intake. Persisted before '
+  'extraction so Slack taps can act on it later and re-shares are detected. '
+  'kind: grocery|food|ask|held|unsupported. status: received|enriched|created|'
+  'candidates|forwarded_to_pantry|needs_header|duplicate|unsupported|held|error.';
+
+-- Overlap lookups for the re-share check (`file_sha256 && $1`).
+CREATE INDEX IF NOT EXISTS intake_batches_file_sha256_gin
+  ON intake_batches USING gin (file_sha256);
+
+CREATE INDEX IF NOT EXISTS intake_batches_transaction_id
+  ON intake_batches (transaction_id) WHERE transaction_id IS NOT NULL;
+
+-- The "Groceries or a meal?" answer, remembered per merchant (plan §2, Codex
+-- #6). A tiny answer table, not merchant master-data: the pattern list in code
+-- decides the obvious cases and this catches the `Romeo's Food Hall`s. Keyed on
+-- the normalised merchant name the router already computes for matching.
+CREATE TABLE IF NOT EXISTS intake_merchant_kinds (
+  merchant_key text PRIMARY KEY,
+  kind         text NOT NULL CHECK (kind IN ('grocery', 'food')),
+  created_at   timestamptz NOT NULL DEFAULT now()
+);
+
+COMMENT ON TABLE intake_merchant_kinds IS
+  'Per-merchant answer to "Groceries or a meal?" from the intake Slack card. '
+  'Consulted after the grocery pattern list; an unknown merchant asks once.';