fix: unify handler response format in multiple handlers

- captcha_handler.go: Fix GenerateCaptcha/VerifyCaptcha to use {code, message, data}
- password_reset_handler.go: Fix all error responses to use {code, message}
- settings_handler.go: Add missing "code" and "message" fields
- sms_handler.go: Fix error responses to use {code, message}
- sso_handler.go: Fix all error responses to use {code, message, data}
- stats_handler.go: Add missing "message" field in success responses
- theme_handler.go: Fix error responses to use {code, message}
- totp_handler.go: Fix all responses to use {code, message, data}

Standardize all JSON responses to {code: 0, message: "success", data: ...} for success
and {code: XXX, message: "..."} for errors.

internal/api/handler/password_reset_handler.go

@@ -33,7 +33,7 @@ func (h *PasswordResetHandler) ForgotPassword(c *gin.Context) {
 	}
 
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -42,13 +42,13 @@ func (h *PasswordResetHandler) ForgotPassword(c *gin.Context) {
 		return
 	}
 
-	c.JSON(http.StatusOK, gin.H{"message": "password reset email sent"})
+	c.JSON(http.StatusOK, gin.H{"code": 0, "message": "password reset email sent"})
 }
 
 func (h *PasswordResetHandler) ValidateResetToken(c *gin.Context) {
 	token := c.Query("token")
 	if token == "" {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "token is required"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "token is required"})
 		return
 	}
 
@@ -58,7 +58,7 @@ func (h *PasswordResetHandler) ValidateResetToken(c *gin.Context) {
 		return
 	}
 
-	c.JSON(http.StatusOK, gin.H{"valid": valid})
+	c.JSON(http.StatusOK, gin.H{"code": 0, "message": "success", "data": gin.H{"valid": valid}})
 }
 
 func (h *PasswordResetHandler) ResetPassword(c *gin.Context) {
@@ -68,7 +68,7 @@ func (h *PasswordResetHandler) ResetPassword(c *gin.Context) {
 	}
 
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -77,7 +77,7 @@ func (h *PasswordResetHandler) ResetPassword(c *gin.Context) {
 		return
 	}
 
-	c.JSON(http.StatusOK, gin.H{"message": "password reset successful"})
+	c.JSON(http.StatusOK, gin.H{"code": 0, "message": "password reset successful"})
 }
 
 // ForgotPasswordByPhoneRequest 短信密码重置请求
@@ -88,13 +88,13 @@ type ForgotPasswordByPhoneRequest struct {
 // ForgotPasswordByPhone 发送短信验证码
 func (h *PasswordResetHandler) ForgotPasswordByPhone(c *gin.Context) {
 	if h.smsService == nil {
-		c.JSON(http.StatusServiceUnavailable, gin.H{"error": "SMS service not configured"})
+		c.JSON(http.StatusServiceUnavailable, gin.H{"code": 503, "message": "SMS service not configured"})
 		return
 	}
 
 	var req ForgotPasswordByPhoneRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -106,7 +106,7 @@ func (h *PasswordResetHandler) ForgotPasswordByPhone(c *gin.Context) {
 	}
 	if code == "" {
 		// 用户不存在，不提示
-		c.JSON(http.StatusOK, gin.H{"message": "verification code sent"})
+		c.JSON(http.StatusOK, gin.H{"code": 0, "message": "success"})
 		return
 	}
 
@@ -121,7 +121,7 @@ func (h *PasswordResetHandler) ForgotPasswordByPhone(c *gin.Context) {
 		return
 	}
 
-	c.JSON(http.StatusOK, gin.H{"message": "verification code sent"})
+	c.JSON(http.StatusOK, gin.H{"code": 0, "message": "success"})
 }
 
 // ResetPasswordByPhoneRequest 短信验证码重置密码请求
@@ -135,7 +135,7 @@ type ResetPasswordByPhoneRequest struct {
 func (h *PasswordResetHandler) ResetPasswordByPhone(c *gin.Context) {
 	var req ResetPasswordByPhoneRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -149,5 +149,5 @@ func (h *PasswordResetHandler) ResetPasswordByPhone(c *gin.Context) {
 		return
 	}
 
-	c.JSON(http.StatusOK, gin.H{"message": "password reset successful"})
+	c.JSON(http.StatusOK, gin.H{"code": 0, "message": "password reset successful"})
 }