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/components/AuditLog.tsx

@@ -0,0 +1,112 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { getAuditLog, type AuditAction } from '@/lib/api';
+
+const PAGE_SIZE = 50;
+
+export function AuditLog() {
+  const [rows, setRows] = useState<AuditAction[]>([]);
+  const [total, setTotal] = useState(0);
+  const [offset, setOffset] = useState(0);
+  const [error, setError] = useState<string | null>(null);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    setLoading(true);
+    getAuditLog(PAGE_SIZE, offset)
+      .then(({ actions, total }) => {
+        setRows(actions);
+        setTotal(total);
+      })
+      .catch((e) => setError(String(e.message)))
+      .finally(() => setLoading(false));
+  }, [offset]);
+
+  if (error) return <p className="text-red-400 text-sm">Error: {error}</p>;
+
+  return (
+    <div className="space-y-4">
+      <div className="flex items-center justify-between">
+        <h1 className="text-xl font-semibold">Audit log</h1>
+        <span className="text-sm text-gray-500">{total} entries</span>
+      </div>
+
+      <div className="rounded-lg border border-gray-800 overflow-hidden">
+        <table className="w-full text-sm">
+          <thead className="bg-gray-900 border-b border-gray-800">
+            <tr>
+              {['Time', 'Admin', 'Action', 'Target'].map((h) => (
+                <th
+                  key={h}
+                  className="text-left px-4 py-2.5 text-xs text-gray-500 font-medium uppercase tracking-wide"
+                >
+                  {h}
+                </th>
+              ))}
+            </tr>
+          </thead>
+          <tbody className="divide-y divide-gray-800">
+            {loading ? (
+              <tr>
+                <td colSpan={4} className="px-4 py-6 text-center text-gray-500">
+                  Loading…
+                </td>
+              </tr>
+            ) : rows.length === 0 ? (
+              <tr>
+                <td colSpan={4} className="px-4 py-6 text-center text-gray-500">
+                  No actions logged yet.
+                </td>
+              </tr>
+            ) : (
+              rows.map((a) => (
+                <tr key={a.id} className="hover:bg-gray-900 transition-colors">
+                  <td className="px-4 py-2.5 text-xs tabular-nums text-gray-400">
+                    {a.createdAt.slice(0, 19).replace('T', ' ')}
+                  </td>
+                  <td className="px-4 py-2.5 font-mono text-xs text-gray-300 truncate max-w-[8rem]">
+                    {a.adminId.slice(0, 8)}…
+                  </td>
+                  <td className="px-4 py-2.5">
+                    <span className="px-1.5 py-0.5 rounded bg-gray-800 text-xs text-gray-200 font-mono">
+                      {a.action}
+                    </span>
+                  </td>
+                  <td className="px-4 py-2.5 text-xs text-gray-400">
+                    {a.targetType && (
+                      <span className="text-gray-500">{a.targetType}: </span>
+                    )}
+                    <span className="font-mono">{a.targetId?.slice(0, 12) ?? '—'}</span>
+                  </td>
+                </tr>
+              ))
+            )}
+          </tbody>
+        </table>
+      </div>
+
+      {total > PAGE_SIZE && (
+        <div className="flex items-center gap-3 text-sm">
+          <button
+            disabled={offset === 0}
+            onClick={() => setOffset(Math.max(0, offset - PAGE_SIZE))}
+            className="px-3 py-1.5 rounded border border-gray-700 disabled:opacity-30 hover:border-gray-500 transition-colors"
+          >
+            Previous
+          </button>
+          <span className="text-gray-500">
+            {offset + 1}–{Math.min(offset + PAGE_SIZE, total)} of {total}
+          </span>
+          <button
+            disabled={offset + PAGE_SIZE >= total}
+            onClick={() => setOffset(offset + PAGE_SIZE)}
+            className="px-3 py-1.5 rounded border border-gray-700 disabled:opacity-30 hover:border-gray-500 transition-colors"
+          >
+            Next
+          </button>
+        </div>
+      )}
+    </div>
+  );
+}