sync app filled in

.project/specs/sync-protocol-v1.md

@@ -112,6 +112,7 @@ Upload client changes and receive server changes + conflicts.
       "type": "update",
       "path": "hello.md",
       "hash": "d4e5f6...",
+      "content": "# Hello\n\nUpdated content\n",
       "size": 50,
       "modified": "2024-01-15T10:05:00Z"
     }
@@ -131,6 +132,7 @@ Upload client changes and receive server changes + conflicts.
       "modified": "2024-01-15T10:02:00Z"
     }
   ],
+  "newSnapshotId": "snap:macbook-pro-1:1234567999",
   "conflicts": [
     {
       "path": "hello.md",
@@ -144,6 +146,10 @@ Upload client changes and receive server changes + conflicts.
 }
 ```
 
+For client create/update changes, the server accepts inline UTF-8 markdown in
+`content` and recomputes the SHA-256 hash before writing the file. If `content`
+is omitted, the supplied `hash` must already exist in the server content store.
+
 ### POST /api/sync/resolve
 
 Resolve conflicts and finalize the sync.