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/server.js

@@ -42,8 +42,30 @@ function createServerStorage({ baseUrl, realtimeUrl } = {}) {
     return { id, ...data };
   }
 
+  // Apply neutral {__type} query constraints client-side. Backend returns all
+  // docs; adapter sorts/limits. Mirrors firebase mock applyConstraints.
+  function applyConstraints(docs, constraints) {
+    let out = [...docs];
+    for (const c of constraints || []) {
+      if (!c || !c.__type) continue;
+      if (c.__type === 'orderBy') {
+        out.sort((a, b) => {
+          const av = a[c.field];
+          const bv = b[c.field];
+          if (av === bv) return 0;
+          const cmp = av > bv ? 1 : -1;
+          return c.dir === 'desc' ? -cmp : cmp;
+        });
+      } else if (c.__type === 'limit') {
+        out = out.slice(0, c.n);
+      }
+    }
+    return out;
+  }
+
   const docSubs = new Map();      // path -> Set<cb>
   const collSubs = new Map();     // collPath -> Set<cb>
+  const collConstraints = new Map(); // collPath -> constraints[] (per collection)
   let ws = null;
   let wsReady = null;
 
@@ -130,11 +152,12 @@ function createServerStorage({ baseUrl, realtimeUrl } = {}) {
       const doc = await storage.getDoc(c.path);
       docCbs.forEach(cb => cb(doc));
     }
-    // collection subscribers at parent path (doc belongs to this collection)
+    // collection subscribers at parent path (apply their stored constraints)
     if (c.parent) {
       const collCbs = collSubs.get(c.parent);
       if (collCbs) {
-        const docs = await storage.getCollection(c.parent);
+        const constraints = collConstraints.get(c.parent) || [];
+        const docs = applyConstraints(await storage.getCollection(c.parent), constraints);
         collCbs.forEach(cb => cb(docs));
       }
     }
@@ -228,8 +251,12 @@ function createServerStorage({ baseUrl, realtimeUrl } = {}) {
 
     subscribeCollection(rawCollPath, cb, queryConstraints = [], errCb) {
       const p = norm(rawCollPath);
-      // Initial value via REST (independent of WS connect).
-      storage.getCollection(p).then(cb).catch(() => {});
+      collConstraints.set(p, queryConstraints || []);
+      // Initial value via REST (independent of WS connect). Apply constraints
+      // client-side — backend returns all docs, adapter sorts/limits.
+      storage.getCollection(p)
+        .then(docs => cb(applyConstraints(docs, queryConstraints || [])))
+        .catch(() => {});
       // WS only for subsequent change notifications.
       ensureWs().then(() => {
         ws.send(JSON.stringify({ type: 'subscribe', kind: 'collection', path: p }));
@@ -243,7 +270,7 @@ function createServerStorage({ baseUrl, realtimeUrl } = {}) {
       disposed = true;
       if (reconnectTimer) { clearTimeout(reconnectTimer); reconnectTimer = null; }
       if (ws) ws.close();
-      docSubs.clear(); collSubs.clear();
+      docSubs.clear(); collSubs.clear(); collConstraints.clear();
       if (typeof cb === 'function') cb();
     },