feat: M1 admin console — all 10 remaining pages + signal/quality/ops infrastructure

Admin console (issues #63–72):
- Event stream viewer: live-tail ring buffer (500 events) with subject/user filters
- Feature store browser: per-user feature vector history from ml/serving
- Model registry panel: MLflow embed at /admin/models
- Experiment dashboard: LinUCB per-user stats (pulls, reward, θ) + bandit reset
- Recommendation log: per-tip explainability (policy, score, features, latency)
- Reward analytics: daily reaction breakdown + per-policy compare
- Data quality widget: missing-feature rate, stale-token rate, daily completeness
- Ops actions: replay-signal, policy enable/disable; user actions link to Users page
- SQL runner: read-only SELECT runner with saved queries
- Health rollup: fan-out to api/ml/sqlite/event-bus with auto-refresh

Backend:
- tip_scores table: logs features+policy+score+latency at every scoring call (#67)
- saved_queries table: per-admin saved SQL (#71)
- Event bus: 500-event ring buffer + tail() API (#63)
- Admin routes: /events, /tips, /reward-analytics, /data-quality, /health,
  /policies, /replay-signal, /sql, /saved-queries endpoints
- /api/ml/* admin-gated proxy to ml/serving (#64, #66)
- Shadow-policy registry in recommender (#56)

ML serving:
- /reset/{user_id}: clear bandit state + feature history (#66)
- /stats/{user_id}: pulls, cumulative reward, estimated mean, θ (#66)
- /features/{user_id}: last 100 feature vectors logged at scoring time (#64)
- Meta (pulls, rewards) persisted alongside A/b matrices

Web:
- Tip action sheet adds Helpful / Not helpful buttons (#62)
- TipFeedback type extended with helpful/not_helpful actions
- Rewards mapped: helpful=+0.5, not_helpful=−0.5

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/admin/src/app/events/page.tsx

@@ -0,0 +1,93 @@
+'use client';
+
+import { useEffect, useRef, useState } from 'react';
+import { AdminShell } from '@/components/AdminShell';
+import { getEvents, StoredEvent } from '@/lib/api';
+
+const SUBJECTS = ['', 'signals.tip', 'signals.task', 'signals.tip.served', 'signals.tip.feedback', 'signals.task.synced'];
+
+export default function EventsPage() {
+  const [events, setEvents] = useState<StoredEvent[]>([]);
+  const [subject, setSubject] = useState('');
+  const [userId, setUserId] = useState('');
+  const [live, setLive] = useState(true);
+  const [error, setError] = useState('');
+  const sinceRef = useRef(0);
+  const timerRef = useRef<ReturnType<typeof setInterval> | null>(null);
+
+  const fetchEvents = async (reset = false) => {
+    try {
+      const since = reset ? 0 : sinceRef.current;
+      const res = await getEvents({ subject: subject || undefined, userId: userId || undefined, limit: 100, since });
+      sinceRef.current = res.nextSince;
+      setEvents((prev) => {
+        const next = reset ? res.events : [...prev, ...res.events];
+        return next.slice(-500); // keep last 500
+      });
+      setError('');
+    } catch (e: any) {
+      setError(e.message);
+    }
+  };
+
+  useEffect(() => {
+    sinceRef.current = 0;
+    fetchEvents(true);
+  }, [subject, userId]);
+
+  useEffect(() => {
+    if (live) {
+      timerRef.current = setInterval(() => fetchEvents(false), 2000);
+    } else if (timerRef.current) {
+      clearInterval(timerRef.current);
+    }
+    return () => { if (timerRef.current) clearInterval(timerRef.current); };
+  }, [live, subject, userId]);
+
+  return (
+    <AdminShell>
+      <div className="space-y-4">
+        <div className="flex items-center justify-between">
+          <h1 className="text-xl font-semibold">Event stream</h1>
+          <div className="flex items-center gap-2">
+            <label className="flex items-center gap-1.5 text-sm text-gray-400 cursor-pointer">
+              <input type="checkbox" checked={live} onChange={(e) => setLive(e.target.checked)} className="accent-indigo-500" />
+              Live
+            </label>
+            <button onClick={() => { sinceRef.current = 0; fetchEvents(true); }} className="text-xs text-gray-400 hover:text-white border border-gray-700 rounded px-2 py-1">
+              Refresh
+            </button>
+          </div>
+        </div>
+
+        <div className="flex gap-3">
+          <select value={subject} onChange={(e) => setSubject(e.target.value)} className="bg-gray-900 border border-gray-700 rounded px-2 py-1 text-sm text-gray-300">
+            {SUBJECTS.map((s) => <option key={s} value={s}>{s || 'All subjects'}</option>)}
+          </select>
+          <input
+            value={userId}
+            onChange={(e) => setUserId(e.target.value)}
+            placeholder="Filter by user ID"
+            className="bg-gray-900 border border-gray-700 rounded px-2 py-1 text-sm text-gray-300 w-64"
+          />
+        </div>
+
+        {error && <p className="text-red-400 text-sm">{error}</p>}
+
+        <div className="font-mono text-xs space-y-1 max-h-[70vh] overflow-y-auto">
+          {events.length === 0 && (
+            <p className="text-gray-500 text-sm">No events yet. Waiting…</p>
+          )}
+          {[...events].reverse().map((e) => (
+            <div key={e.id} className="flex gap-3 border-b border-gray-800 pb-1">
+              <span className="text-gray-600 w-12 flex-shrink-0">{e.id}</span>
+              <span className="text-gray-500 w-24 flex-shrink-0">{e.ts.slice(11, 19)}</span>
+              <span className="text-indigo-400 w-40 flex-shrink-0">{e.subject}</span>
+              <span className="text-gray-300 break-all">{JSON.stringify(e.payload)}</span>
+            </div>
+          ))}
+        </div>
+      </div>
+    </AdminShell>
+  );
+}