feat: add stuff

docs/api.md

@@ -55,6 +55,20 @@ Sync semantics:
   The response lists `acknowledgedEventIds` (stored, including events already stored by an earlier sync)
   and `rejectedEvents` (`[{ id, reason }]`, invalid and never stored). The terminal removes both from its
   outbox. An invalid event never fails the sync. At most 1000 events per sync.
+- `products` (optional) is the terminal's **complete** product catalog:
+  `[{ id, name, category?, priceInCents, stock }]`, where `stock` is an integer (may be negative) or `null` when
+  the terminal doesn't track stock for that product. Products left out are removed from the dashboard. When the
+  field is omitted (older app versions) the stored products are left alone. An invalid product is skipped and
+  logged, never failing the sync. At most 2000 products.
+- `stockAdjustments` in the response lists **every** pending stock change requested from the dashboard
+  for the venue, oldest first: `[{ id, productId, type, quantity, note, requestedBy, createdAt }]`.
+  `type: "add"` changes the stock by `quantity` (negative takes stock out); `type: "set"` makes the stock
+  `quantity` (a count, ≥ 0, and starts tracking an untracked product). They are re-sent on every sync until the
+  terminal reports an outcome, so the terminal must apply each id only once.
+- `stockAdjustmentResults` (optional) reports outcomes: `[{ id, status: "applied" | "rejected", stockAfter?, reason? }]`
+  (`stockAfter` is required for `applied`). The response lists `acknowledgedStockAdjustmentResultIds` and
+  `rejectedStockAdjustmentResults` (`[{ id, reason }]`); the terminal drops both from its outbox. The terminal's
+  outcome is recorded even if the adjustment was cancelled on the dashboard in the meantime.
 
 ### Tabs
 `GET /venues/:venueId/tabs` - List open tabs
@@ -75,6 +89,14 @@ Names match case-insensitively and keep their existing spelling; `replace` also
 `GET /venues/:venueId/reminders?customerName=` - Reminder history, optionally for one customer
 `POST /venues/:venueId/reminders/test/:plannedTabId` - Send a test email (admin)
 
+### Stock
+`GET /venues/:venueId/stock` - The terminal's products with stock, low stock level and pending adjustments
+`GET /venues/:venueId/stock/adjustments?productId=&limit=&offset=` - Stock adjustment history, newest first
+`POST /venues/:venueId/stock/adjustments` - Request stock changes (admins and viewers): `{ adjustments: [{ productId, type: 'add' | 'set', quantity, note? }] }`.
+  `add` takes a non-zero quantity (negative for breakage) and needs a tracked product; `set` takes 0 or more.
+`POST /venues/:venueId/stock/adjustments/:id/cancel` - Cancel an adjustment the terminal hasn't received yet (admins and viewers)
+`PUT /venues/:venueId/stock/products/:productId` - Set `{ lowStockThreshold: number | null }` (admin, dashboard only)
+
 ### Commands
 `POST /venues/:venueId/commands` - Create a command
 `GET /venues/:venueId/commands` - List command history