feat: add captcha support for user login and enhance user profile page

- Refactored userLogin function to include captcha handling.
- Introduced getCaptchaConfig API to fetch captcha configuration.
- Added Captcha component to handle different captcha providers (hCaptcha, reCaptcha, Turnstile).
- Updated LoginForm component to integrate captcha verification.
- Created UserProfile component to display user information with avatar.
- Implemented getUserByUsername API to fetch user details by username.
- Removed deprecated LoginRequest interface from user model.
- Enhanced navbar and layout with animation effects.
- Removed unused user page component and added dynamic user profile routing.
- Updated localization files to include captcha-related messages.
- Improved Gravatar component for better avatar handling.

internal/dto/user.go

@@ -70,6 +70,10 @@ type GetUserReq struct {
 	UserID uint `json:"user_id"`
 }
 
+type GetUserByUsernameReq struct {
+	Username string `json:"username"`
+}
+
 type GetUserResp struct {
 	User UserDto `json:"user"` // 用户信息
 }