feat: add user preferences dashboard

- Add /preferences route and preferences.html template for user settings
- Implement username, email, password, and theme update functionality
- Add account deletion feature with confirmation
- Add navigation link to preferences from dashboard
- Create API endpoints:
  - PUT /api/user/username - Update username
  - PUT /api/user/email - Update email address
  - PUT /api/user/password - Change password with verification
  - DELETE /api/user/account - Delete user account
- Add database queries for user updates and account deletion
- Create Bruno API testing files for all user preference endpoints
- Add proper validation, error handling, and security checks

internal/database/connection.go

@@ -7,12 +7,13 @@ import (
 )
 
 func NewConnection(databaseURL string) (*pgxpool.Pool, error) {
-	pool, err := pgxpool.New(context.Background(), databaseURL)
+	config, err := pgxpool.ParseConfig(databaseURL)
 	if err != nil {
 		return nil, err
 	}
 
-	if err := pool.Ping(context.Background()); err != nil {
+	pool, err := pgxpool.NewWithConfig(context.Background(), config)
+	if err != nil {
 		return nil, err
 	}