fix(openai): move TTFT metric mode to admin settings

frontend/src/views/admin/SettingsView.vue

@@ -5268,6 +5268,32 @@
                   </p>
                 </div>
 
+              <!-- OpenAI Responses 首 token 统计 -->
+              <div class="border-b border-gray-100 pb-5 dark:border-dark-700 md:col-span-2">
+                <label
+                  for="openai-ttft-mode"
+                  class="text-sm font-medium text-gray-700 dark:text-gray-300"
+                >
+                  {{ t("admin.settings.gatewayForwarding.openaiTTFTMode") }}
+                </label>
+                <select
+                  id="openai-ttft-mode"
+                  v-model="form.openai_ttft_mode"
+                  class="input mt-2 w-full"
+                  data-testid="openai-ttft-mode"
+                >
+                  <option value="semantic">
+                    {{ t("admin.settings.gatewayForwarding.openaiTTFTModeSemantic") }}
+                  </option>
+                  <option value="visible">
+                    {{ t("admin.settings.gatewayForwarding.openaiTTFTModeVisible") }}
+                  </option>
+                </select>
+                <p class="mt-1.5 text-xs text-gray-500 dark:text-gray-400">
+                  {{ t("admin.settings.gatewayForwarding.openaiTTFTModeHint") }}
+                </p>
+              </div>
+
               <!-- Fingerprint Unification -->
               <div class="flex items-center justify-between">
                 <div>
@@ -9735,6 +9761,7 @@ const form = reactive<SettingsForm>({
   openai_advanced_scheduler_weight_previous_response: "",
   openai_advanced_scheduler_weight_session_sticky: "",
   // Gateway forwarding behavior
+  openai_ttft_mode: "semantic",
   enable_fingerprint_unification: true,
   enable_metadata_passthrough: false,
   enable_cch_signing: false,
@@ -11308,6 +11335,8 @@ async function saveSettings() {
       min_claude_code_version: form.min_claude_code_version,
       max_claude_code_version: form.max_claude_code_version,
       allow_ungrouped_key_scheduling: form.allow_ungrouped_key_scheduling,
+      openai_ttft_mode:
+        form.openai_ttft_mode === "visible" ? "visible" : "semantic",
       enable_fingerprint_unification: form.enable_fingerprint_unification,
       enable_metadata_passthrough: form.enable_metadata_passthrough,
       enable_cch_signing: form.enable_cch_signing,

frontend/src/views/admin/__tests__/SettingsView.spec.ts

@@ -464,6 +464,7 @@ const baseSettingsResponse = {
   min_claude_code_version: "",
   max_claude_code_version: "",
   allow_ungrouped_key_scheduling: false,
+  openai_ttft_mode: "semantic",
   enable_fingerprint_unification: true,
   enable_metadata_passthrough: false,
   enable_cch_signing: false,
@@ -1363,6 +1364,27 @@ describe("admin SettingsView payment visible method controls", () => {
     expect(payload.grok_cross_client_model_map_enabled).toBe(false);
   });
 
+  it("loads and saves the OpenAI Responses first-token metric mode", async () => {
+    getSettings.mockResolvedValueOnce({
+      ...baseSettingsResponse,
+      openai_ttft_mode: "visible",
+    });
+    const wrapper = mountView();
+
+    await flushPromises();
+    await openGatewayTab(wrapper);
+
+    const modeSelect = wrapper.get('[data-testid="openai-ttft-mode"]');
+    expect((modeSelect.element as HTMLSelectElement).value).toBe("visible");
+
+    await modeSelect.setValue("semantic");
+    await wrapper.find("form").trigger("submit.prevent");
+    await flushPromises();
+
+    const payload = updateSettings.mock.calls.at(-1)?.[0] as Record<string, unknown>;
+    expect(payload.openai_ttft_mode).toBe("semantic");
+  });
+
   it("loads fail-safe-off Ollama Cloud usage refresh settings and saves an explicit opt-in", async () => {
     const wrapper = mountView();