ws adapter: match main truth (id injection + setDoc merge)

- getDoc/getCollection/subscribe inject {id,...data} (main firebase shape)
- getCollection normalizes backend {id,data}[] OR bare data[] → {id,...data}
- setDoc(opts.merge) → PATCH (create-on-miss); else PUT (replace)
- ws-reconnect test asserts id now present

24/24 server green. All suites green: App 83, shared 91, server 24.

server/tests/ws-reconnect.test.js

@@ -48,7 +48,7 @@ describe('BUG-8: ws adapter reconnect after drop', () => {
       await flush(1000);
 
       const last = calls[calls.length - 1];
-      expect(last).toEqual({ name: 'V2' });
+      expect(last).toEqual({ id: 'a', name: 'V2' });
     } finally {
       await new Promise(r => storage.dispose(r));
     }