fix(auth): add submit Turnstile widget in email verify flow

- 邮箱验证码流程中，提交注册前要求重新完成 Turnstile 验证
- 修复发送验证码后 token 被清空导致注册时缺少 turnstile_token 的问题
- submit/resend 两个 widget 通过 showResendTurnstile 互斥显示

backend/internal/handler/auth_handler.go

@@ -113,8 +113,7 @@ func (h *AuthHandler) Register(c *gin.Context) {
 		return
 	}
 
-	// Turnstile 验证 — 始终执行，防止绕过
-	// TODO: 确认前端在提交邮箱验证码注册时也传递了 turnstile_token
+	// Turnstile 验证 — 始终执行，防止机器人自动化注册
 	if err := h.authService.VerifyTurnstile(c.Request.Context(), req.TurnstileToken, ip.GetClientIP(c)); err != nil {
 		response.ErrorFrom(c, err)
 		return

frontend/src/views/auth/EmailVerifyView.vue

@@ -69,6 +69,20 @@
           </div>
         </div>
 
+        <!-- Turnstile Widget for Submit -->
+        <div v-if="turnstileEnabled && turnstileSiteKey && !showResendTurnstile">
+          <TurnstileWidget
+            ref="submitTurnstileRef"
+            :site-key="turnstileSiteKey"
+            @verify="onSubmitTurnstileVerify"
+            @expire="onSubmitTurnstileExpire"
+            @error="onSubmitTurnstileError"
+          />
+          <p v-if="errors.submitTurnstile" class="input-error-text mt-2 text-center">
+            {{ errors.submitTurnstile }}
+          </p>
+        </div>
+
         <!-- Turnstile Widget for Resend -->
         <div v-if="turnstileEnabled && turnstileSiteKey && showResendTurnstile">
           <TurnstileWidget
@@ -101,7 +115,7 @@
         </transition>
 
         <!-- Submit Button -->
-        <button type="submit" :disabled="isLoading || !verifyCode" class="btn btn-primary w-full">
+        <button type="submit" :disabled="isLoading || !verifyCode || (turnstileEnabled && !submitTurnstileToken)" class="btn btn-primary w-full">
           <svg
             v-if="isLoading"
             class="-ml-1 mr-2 h-4 w-4 animate-spin text-white"
@@ -209,6 +223,10 @@ const turnstileEnabled = ref<boolean>(false)
 const turnstileSiteKey = ref<string>('')
 const siteName = ref<string>('Sub2API')
 
+// Turnstile for submit
+const submitTurnstileRef = ref<InstanceType<typeof TurnstileWidget> | null>(null)
+const submitTurnstileToken = ref<string>('')
+
 // Turnstile for resend
 const turnstileRef = ref<InstanceType<typeof TurnstileWidget> | null>(null)
 const resendTurnstileToken = ref<string>('')
@@ -216,7 +234,8 @@ const showResendTurnstile = ref<boolean>(false)
 
 const errors = ref({
   code: '',
-  turnstile: ''
+  turnstile: '',
+  submitTurnstile: ''
 })
 
 // ==================== Lifecycle ====================
@@ -284,6 +303,21 @@ function startCountdown(seconds: number): void {
 
 // ==================== Turnstile Handlers ====================
 
+function onSubmitTurnstileVerify(token: string): void {
+  submitTurnstileToken.value = token
+  errors.value.submitTurnstile = ''
+}
+
+function onSubmitTurnstileExpire(): void {
+  submitTurnstileToken.value = ''
+  errors.value.submitTurnstile = 'Verification expired, please try again'
+}
+
+function onSubmitTurnstileError(): void {
+  submitTurnstileToken.value = ''
+  errors.value.submitTurnstile = 'Verification failed, please try again'
+}
+
 function onTurnstileVerify(token: string): void {
   resendTurnstileToken.value = token
   errors.value.turnstile = ''
@@ -385,7 +419,7 @@ async function handleVerify(): Promise<void> {
       email: email.value,
       password: password.value,
       verify_code: verifyCode.value.trim(),
-      turnstile_token: initialTurnstileToken.value || undefined,
+      turnstile_token: submitTurnstileToken.value || undefined,
       promo_code: promoCode.value || undefined,
       invitation_code: invitationCode.value || undefined
     })
@@ -399,6 +433,12 @@ async function handleVerify(): Promise<void> {
     // Redirect to dashboard
     await router.push('/dashboard')
   } catch (error: unknown) {
+    // Reset submit turnstile on error
+    if (submitTurnstileRef.value) {
+      submitTurnstileRef.value.reset()
+      submitTurnstileToken.value = ''
+    }
+
     const err = error as { message?: string; response?: { data?: { detail?: string } } }
 
     if (err.response?.data?.detail) {