feat(auth): user-management audit log (table + record sites + /api/audit endpoint)

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

src/data/database.test.ts

@@ -40,6 +40,13 @@ describe("database", () => {
     expect(sessionColNames).toEqual(["createdAt", "expiresAt", "id", "lastSeenAt", "userId"]);
   });
 
+  it("creates user_audit table on init", () => {
+    const tables = botDb.db
+      .prepare("SELECT name FROM sqlite_master WHERE type='table' ORDER BY name")
+      .all() as Array<{ name: string }>;
+    expect(tables.map((t) => t.name)).toContain("user_audit");
+  });
+
   it("records and retrieves play history", () => {
     botDb.addPlayHistory({
       botId: "bot1",