feat(F-105): completed feature

work/artifacts/F-105/security.json

@@ -0,0 +1,13 @@
+{
+  "feature_id": "F-105",
+  "agent": "security",
+  "verdict": "APPROVED",
+  "summary": "Preference writes are authenticated, owner-scoped and strictly validated; SQL stays parameterized.",
+  "evidence": [
+    "PATCH /users/:id keeps requireOwnerOrAdmin guard",
+    "zod strict schema allows only three boolean keys; unknown keys rejected",
+    "preferences merged via COALESCE(preferences,'{}')||$n::jsonb parameterized query",
+    "No secret or PII exposure added"
+  ],
+  "timestamp": "2026-08-21T06:20:30Z"
+}