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/storage/firebase.js

@@ -130,8 +130,15 @@ export function createFirebaseStorage() {
 
     subscribeCollection(collectionPath, cb, queryConstraints = [], errCb) {
       recordAdapterCall({ fn: 'subscribeCollection', path: collectionPath });
-      const q = queryConstraints.length > 0
-        ? query(collection(db, collectionPath), ...queryConstraints)
+      // queryConstraints = neutral {__type} builders (from index.js).
+      // Translate to SDK orderBy/limit.
+      const sdkConstraints = queryConstraints.map(c => {
+        if (c.__type === 'orderBy') return orderBy(c.field, c.dir);
+        if (c.__type === 'limit') return limit(c.n);
+        return c; // pass-through (forward compat)
+      });
+      const q = sdkConstraints.length > 0
+        ? query(collection(db, collectionPath), ...sdkConstraints)
         : collection(db, collectionPath);
       return onSnapshot(q, (snap) => {
         cb(snap.docs.map(d => ({ id: d.id, ...d.data() })));
@@ -146,7 +153,8 @@ export function createFirebaseStorage() {
 }
 
 // Re-export SDK pieces App.js uses directly (until full refactor).
+// orderBy/limit NOT re-exported: App uses neutral builders from index.js.
 export {
   doc, setDoc, updateDoc, deleteDoc, addDoc, collection, onSnapshot,
-  query, orderBy, limit, writeBatch,
+  query, writeBatch,
 };