Implement upsert label flow and use-based mark gone handling

README.md

@@ -147,8 +147,8 @@ Default endpoint placeholders live in [`src/app/config.js`](/Users/blaz/PycharmP
 
 Expected shapes today:
 
-- Kitchen-scoped application resources use:
-  `/{database}/kitchen/{kitchen_id}/{resource}`
+- Kitchen application resources use database-scoped routes:
+  `/{database}/kitchen/{resource}`
 - User application key management uses:
   `/{database}/user/application/`
 
@@ -165,14 +165,20 @@ Expected shapes today:
   Returns the current stock review list.
 - `GET /{database}/kitchen/items/{uuid_b64}`
   Returns one item detail payload.
+- `GET /{database}/kitchen/changes`
+  Returns `{ since, next_cursor, changes }` feed payload for item/stock updates.
+- `POST /{database}/kitchen/items/upsert?mode=preview|apply`
+  Used by label submit flow for create-or-update behavior and conflict-safe matching.
 - `POST /{database}/kitchen/items?label=1`
-  Creates a stock item plus label-related output on the backend side.
+  Used for label image preview rendering.
 - `POST /{database}/kitchen/items?label=1&preview=1`
   Returns an image blob, `{ imageUrl }`, or `{ imageSvg }` for in-browser preview.
 - `POST /{database}/kitchen/items/{uuid_b64}/stock`
   Updates measured or descriptive stock state using `{ quantity }` or `{ level }`.
+- `POST /{database}/kitchen/items/{uuid_b64}/use`
+  Marks an item used up (`gone`) via stock-event semantics.
 - `DELETE /{database}/kitchen/items/{uuid_b64}`
-  Marks an individual stock item gone.
+  Compatibility fallback when `/use` is not available on the backend.
 - `GET /{database}/kitchen/locations`
   Returns a nested location tree.
 
@@ -181,4 +187,5 @@ Expected shapes today:
 - Hash-based routing is used to keep static deployment simple.
 - Local storage only keeps non-sensitive app config, session payload, active kitchen, and label draft state.
 - Kitchen context now lives in the URL path instead of a custom header.
-- `includeKitchen: false` in the API client only removes the kitchen path segment; it does not disable bearer authentication.
+- The API client now builds database-scoped kitchen routes by default; it always keeps bearer authentication handling separate from URL shaping.
+- Label submit now uses upsert-first apply semantics; auto-print is intentionally deferred.