test(data): validate ng-eventually read filter on the real ORM set

Adds a @data scenario (workshop/read-filter) that enables the lib's read filter on the
real reactive ORM set (via a FilterProbe + setupReadFilter harness helper, granting each
participation to its own user) and asserts useShape returns only the target user's
participations. Validates the trickiest piece — filtering a live DeepSignalSet — against the
broker. @data 9/9. Doc: read filter marked implemented & validated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/shared/test-harness/harness-ng.tsx

@@ -12,6 +12,7 @@ import { createRoot } from 'react-dom/client';
 import { NextGraphProvider, useNextGraph } from '../context/NextGraphContext';
 import { FestipodDataProvider, useFestipodData } from '../context/FestipodDataContext';
 import { useShape } from '@ng-eventually/client';
+import { setGrantOf, setCurrentUser } from '@ng-eventually/client/polyfill';
 import type { DeepSignalSet } from '@ng-eventually/client';
 import {
   FpEventShapeType,
@@ -67,6 +68,8 @@ function ConnectedHarness() {
   const participations = useShape(FpParticipationShapeType, privateNuri) as DeepSignalSet<FpParticipation>;
 
   const [bridgeReady, setBridgeReady] = useState(false);
+  // Read-filter validation: when set, <FilterProbe> mounts a filtered useShape.
+  const [filterUser, setFilterUser] = useState<string | null>(null);
 
   useEffect(() => {
     // Small delay for useShape to populate
@@ -146,6 +149,19 @@ function ConnectedHarness() {
         loadTestData() {
           return bootstrapWallet(events as any, users as any, participations as any);
         },
+
+        /**
+         * Enable the lib's READ FILTER on the real ORM set: each participation is
+         * granted to its own `user`, and the current user is `user`. <FilterProbe>
+         * then exposes window.__readFilter with the filtered participations.
+         */
+        setupReadFilter(user: string) {
+          setGrantOf((item: any) =>
+            item && item.user ? { read: [item.user], write: [item.user] } : undefined,
+          );
+          setCurrentUser(user);
+          setFilterUser(user);
+        },
       };
 
       console.log('[HarnessNG] Ready — events:', events.size, 'users:', users.size,
@@ -157,7 +173,30 @@ function ConnectedHarness() {
     return () => clearTimeout(timer);
   }, [events, users, participations, ngCtx, appData]);
 
-  return <div id="harness-status">{bridgeReady ? 'READY' : 'LOADING_SHAPES'}</div>;
+  return (
+    <>
+      <div id="harness-status">{bridgeReady ? 'READY' : 'LOADING_SHAPES'}</div>
+      {filterUser && privateNuri && <FilterProbe privateNuri={privateNuri} />}
+    </>
+  );
+}
+
+// ============================================================================
+// FilterProbe — subscribes participations AFTER the read filter is enabled, so
+// useShape returns a filtered view. Exposes window.__readFilter for the @data
+// scenario validating the read filter on the real ORM set.
+// ============================================================================
+
+function FilterProbe({ privateNuri }: { privateNuri: string }) {
+  const set = useShape(FpParticipationShapeType, privateNuri) as DeepSignalSet<FpParticipation>;
+  useEffect(() => {
+    (window as any).__readFilter = {
+      ready: true,
+      count: set.size,
+      users: [...set].map(p => p.user),
+    };
+  }, [set]);
+  return null;
 }
 
 // ============================================================================