feat: add master password hint functionality

- Updated user model to include masterPasswordHint.
- Modified sync handler to return masterPasswordHint.
- Implemented password hint retrieval in public API.
- Enhanced user profile management to allow updating of password hint.
- Added UI components for displaying and editing password hint.
- Updated localization files for new password hint strings.
- Improved rate limiting for sensitive public requests.
- Adjusted database schema to accommodate master password hint.

migrations/0001_init.sql

@@ -13,6 +13,7 @@ CREATE TABLE IF NOT EXISTS users (
   id TEXT PRIMARY KEY,
   email TEXT NOT NULL UNIQUE,
   name TEXT,
+  master_password_hint TEXT,
   master_password_hash TEXT NOT NULL,
   key TEXT NOT NULL,
   private_key TEXT,