Check the CloudKit schema when packaging and show broken iCloud sync

api/openapi.yaml

@@ -1015,6 +1015,20 @@ paths:
           description: Switched to the WebSocket protocol.
         "400": { $ref: "#/components/responses/Error" }
 
+  /api/clients/sync:
+    put:
+      operationId: setClientSync
+      description: Records how the calling app's iCloud sync last went, for the clients in the status. The Byre-Client and Byre-Host headers name the client.
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema: { $ref: "#/components/schemas/ClientSync" }
+      responses:
+        "204":
+          description: Recorded.
+        "400": { $ref: "#/components/responses/Error" }
+
   /api/clients/transfers/{transferId}:
     parameters:
       - { name: transferId, in: path, required: true, schema: { type: string } }
@@ -1984,6 +1998,16 @@ components:
         commit: { type: string, description: The git commit the app was built from, from its Byre-Commit header; empty when the client sent none. }
         connected_at: { type: string, format: date-time, description: When the client's WebSocket connected. }
         last_action_at: { type: string, format: date-time, description: When byre last received a request the human made from this client since byre started; absent when none. }
+        sync: { $ref: "#/components/schemas/ClientSync" }
+
+    ClientSync:
+      type: object
+      required: [ok, at]
+      description: The app's latest finished iCloud sync operation; absent from a client until it reports one.
+      properties:
+        ok: { type: boolean, description: Whether that operation succeeded. }
+        error: { type: string, description: Why it failed; absent when ok. }
+        at: { type: string, format: date-time, description: When it finished. }
 
     ClientRequest:
       type: object