fix(storage): neutral queryConstraints honored by both adapters

Bug: server adapter accepted queryConstraints (orderBy/limit) but ignored them.
Combat log [orderBy('timestamp','desc'), limit(500)] returned ALL logs unordered
in server mode — unbounded growth. No test caught it: shared contract tested
subscribeCollection with 0 constraints; the firebase-only queryConstraint test
never touched the server adapter. Parity gap.

Fix (Plan A — neutral shape):
- index.js: orderBy()/limit() now NEUTRAL builders returning {__type}. Removed
  SDK orderBy/limit re-export.
- firebase.js: subscribeCollection translates neutral -> SDK query constraints.
- server.js: applyConstraints() helper sorts/limits client-side (backend returns
  all). Constraints stored per collection, applied on initial fetch + WS change.
- contract.js: added 3 queryConstraint tests (orderBy desc, limit, no-constraints)
  to SHARED contract — both adapters now run identical assertions.
- firebase.contract.test.js: removed now-redundant firebase-only constraint
  block (covered by shared contract).

Data impact: ZERO. Constraints are query-time only, never stored. Combat log
docs keep timestamp field. No Firebase data migration needed.

208 tests green.

src/tests/firebase.contract.test.js

@@ -1,13 +1,15 @@
 // Firebase adapter contract test.
-// Runs the SAME storage contract as ws (src/storage/contract.js)
+// Runs the SAME storage contract as server (src/storage/contract.js)
 // against createFirebaseStorage. The SDK is mocked via src/__mocks__/firebase/*,
 // so this proves the adapter translates contract calls -> SDK calls correctly
-// (path handling, merge semantics, subscribe) without hitting network.
+// (path handling, merge semantics, subscribe, queryConstraints) without network.
+//
+// queryConstraints (orderBy + limit) now tested in shared contract for BOTH
+// adapters — no separate firebase-only block needed here.
 
 import { initFirebase, createFirebaseStorage } from '../storage/firebase';
 import { runStorageContract } from '../storage/contract';
-import { resetMockDb, MOCK_DB } from '../__mocks__/firebase/_mock-db';
-import { orderBy, limit } from '../__mocks__/firebase/firestore';
+import { resetMockDb } from '../__mocks__/firebase/_mock-db';
 
 // Firebase mock DB is shared global state. Reset before each factory so
 // contract tests are isolated.
@@ -17,39 +19,3 @@ runStorageContract('firebase', () => {
   if (!ok) throw new Error('initFirebase failed under mocked env');
   return createFirebaseStorage();
 });
-
-// Firebase-only: queryConstraints (orderBy + limit) must flow through
-// subscribeCollection. main App passes LOG_QUERY = [orderBy('timestamp','desc'),
-// limit(500)] for the combat log. Adapter forwards them to the SDK; this proves
-// the whole chain sorts + caps, not just dumps raw.
-describe('firebase adapter: queryConstraints', () => {
-  let storage;
-  beforeEach(() => {
-    resetMockDb();
-    initFirebase();
-    storage = createFirebaseStorage();
-  });
-
-  test('subscribeCollection honors orderBy desc', async () => {
-    MOCK_DB.set('logs/a', { message: 'A', timestamp: 100 });
-    MOCK_DB.set('logs/b', { message: 'B', timestamp: 300 });
-    MOCK_DB.set('logs/c', { message: 'C', timestamp: 200 });
-
-    const result = await new Promise((resolve) => {
-      storage.subscribeCollection('logs', resolve, [orderBy('timestamp', 'desc')]);
-    });
-    expect(result.map(d => d.message)).toEqual(['B', 'C', 'A']);
-  });
-
-  test('subscribeCollection honors limit', async () => {
-    for (let i = 0; i < 5; i++) {
-      MOCK_DB.set(`logs/l${i}`, { message: `L${i}`, timestamp: i });
-    }
-
-    const result = await new Promise((resolve) => {
-      storage.subscribeCollection('logs', resolve, [orderBy('timestamp', 'desc'), limit(3)]);
-    });
-    expect(result).toHaveLength(3);
-    expect(result.map(d => d.message)).toEqual(['L4', 'L3', 'L2']);
-  });
-});