sync app filled in

.project/specs/simplesync-protocol.md

@@ -192,6 +192,7 @@ Response:
       "type": "update",
       "path": "guide.md",
       "hash": "client-hash",
+      "content": "# Guide\n\nClient edit\n",
       "size": 58,
       "modified": "2026-05-14T12:05:00Z"
     }
@@ -212,6 +213,7 @@ Response:
       "modified": "2026-05-14T12:03:00Z"
     }
   ],
+  "newSnapshotId": "snap:device:new-timestamp",
   "conflicts": [
     {
       "path": "guide.md",
@@ -225,6 +227,11 @@ Response:
 }
 ```
 
+For create/update deltas, native clients should send inline UTF-8 markdown in
+`content`. The server stores the bytes content-addressably, verifies any claimed
+`hash`, writes the markdown into the content tree, and returns a fresh
+`newSnapshotId` for the client's next sync request.
+
 ### Resolve
 
 `POST /api/sync/resolve`