feat(F-105): completed feature

work/artifacts/F-105/qa.json

@@ -0,0 +1,13 @@
+{
+  "feature_id": "F-105",
+  "agent": "qa",
+  "verdict": "APPROVED",
+  "summary": "Backend tests and builds green; migration applied; preferences merge verified against live DB; services restarted healthy.",
+  "evidence": [
+    "npm test: 133 passed, 56 skipped; backend and frontend builds exit 0",
+    "Migration 035_users_preferences applied",
+    "Repo smoke: partial merge produced {orderUpdates:true,newsletter:true,promos:false}, revert ok",
+    "health/frontend/admin HTTP 200 after restart; verify.sh green"
+  ],
+  "timestamp": "2026-08-21T06:21:00Z"
+}