feat: implement account settings and API tokens management

- Added SettingsComponent for user profile management, including display name and password change functionality.
- Introduced TokensComponent for managing API tokens, including creation and revocation.
- Created LayoutComponent for consistent application layout with navigation and user information.
- Established main application structure in index.html and main.ts.
- Integrated Tailwind CSS for styling and responsive design.
- Configured TypeScript settings for strict type checking and module resolution.

ts/models/db.ts

@@ -0,0 +1,57 @@
+/**
+ * Database connection singleton
+ */
+
+import * as plugins from '../plugins.ts';
+
+let dbInstance: plugins.smartdata.SmartdataDb | null = null;
+
+/**
+ * Initialize database connection
+ */
+export async function initDb(config: {
+  mongoDbUrl: string;
+  mongoDbName?: string;
+}): Promise<plugins.smartdata.SmartdataDb> {
+  if (dbInstance) {
+    return dbInstance;
+  }
+
+  dbInstance = new plugins.smartdata.SmartdataDb({
+    mongoDbUrl: config.mongoDbUrl,
+    mongoDbName: config.mongoDbName || 'stackregistry',
+  });
+
+  await dbInstance.init();
+  console.log('Database connected successfully');
+
+  return dbInstance;
+}
+
+/**
+ * Get database instance (must call initDb first)
+ */
+export function getDb(): plugins.smartdata.SmartdataDb {
+  if (!dbInstance) {
+    throw new Error('Database not initialized. Call initDb() first.');
+  }
+  return dbInstance;
+}
+
+/**
+ * Close database connection
+ */
+export async function closeDb(): Promise<void> {
+  if (dbInstance) {
+    await dbInstance.close();
+    dbInstance = null;
+    console.log('Database connection closed');
+  }
+}
+
+/**
+ * Check if database is connected
+ */
+export function isDbConnected(): boolean {
+  return dbInstance !== null;
+}