feat: add configurable Antigravity user agent version

frontend/src/views/admin/SettingsView.vue

@@ -3451,6 +3451,36 @@
                 </div>
                 <Toggle v-model="form.rewrite_message_cache_control" />
               </div>
+
+              <!-- Antigravity UA 版本 -->
+              <div>
+                <label
+                  class="mb-2 block text-sm font-medium text-gray-700 dark:text-gray-300"
+                >
+                  {{
+                    t(
+                      "admin.settings.gatewayForwarding.antigravityUserAgentVersion",
+                    )
+                  }}
+                </label>
+                <input
+                  v-model="form.antigravity_user_agent_version"
+                  type="text"
+                  class="input max-w-xs font-mono text-sm"
+                  :placeholder="
+                    t(
+                      'admin.settings.gatewayForwarding.antigravityUserAgentVersionPlaceholder',
+                    )
+                  "
+                />
+                <p class="mt-1.5 text-xs text-gray-500 dark:text-gray-400">
+                  {{
+                    t(
+                      "admin.settings.gatewayForwarding.antigravityUserAgentVersionHint",
+                    )
+                  }}
+                </p>
+              </div>
             </div>
           </div>
           <!-- Web Search Emulation -->
@@ -6571,6 +6601,7 @@ const form = reactive<SettingsForm>({
   enable_cch_signing: false,
   enable_anthropic_cache_ttl_1h_injection: false,
   rewrite_message_cache_control: false,
+  antigravity_user_agent_version: "",
   // Balance & quota notification
   balance_low_notify_enabled: false,
   balance_low_notify_threshold: 0,
@@ -7642,6 +7673,8 @@ async function saveSettings() {
       enable_anthropic_cache_ttl_1h_injection:
         form.enable_anthropic_cache_ttl_1h_injection,
       rewrite_message_cache_control: form.rewrite_message_cache_control,
+      antigravity_user_agent_version:
+        form.antigravity_user_agent_version?.trim() || "",
       // Payment configuration
       payment_enabled: form.payment_enabled,
       risk_control_enabled: form.risk_control_enabled,