feat: Add Remember Me to admin login

- Added Remember Me checkbox to login form with 30-day session expiry
- Sessions default to 1 day; when remember_me=true, expire in 30 days
- User info stored in localStorage (persistent) vs sessionStorage (per-tab)
- initAuth() checks localStorage first, then sessionStorage for user info

admin_server.py

@@ -834,9 +834,11 @@ def login(body: dict):
         raise HTTPException(status_code=401, detail="Invalid username or password")
 
     token = _generate_token()
+    remember_me = body.get("remember_me", False)
+    expiry = "+30 days" if remember_me else "+1 day"
     conn.execute(
-        "INSERT INTO sessions (user_id, token, expires_at) VALUES (?, ?, datetime('now', '+1 day'))",
-        (row["id"], token),
+        "INSERT INTO sessions (user_id, token, expires_at) VALUES (?, ?, datetime('now', ?))",
+        (row["id"], token, expiry),
     )
     conn.commit()
     _log_activity(conn, "login", "user", row["id"],