feat(config): 添加模型助手功能以选择和管理模型

本次提交主要包含以下更改：

1. **后端更新**:
   - 在 `app/service/config/config_service.py` 中新增 `fetch_ui_models` 方法，用于获取可用于 UI 的模型列表，并处理相关的错误情况。
   - 在 `app/router/config_routes.py` 中新增 `/ui/models` 路由，提供模型列表的 API 接口，并添加身份验证逻辑。

2. **前端更新**:
   - 在 `app/static/js/config_editor.js` 中实现模型助手的功能，包括模型列表的加载、搜索和选择。
   - 在 `app/templates/config_editor.html` 中添加模型助手的模态框和相关的 UI 元素，允许用户从列表中选择模型。

这些更改旨在增强用户体验，使用户能够更方便地选择和管理模型，提高配置界面的交互性和功能性。

app/static/js/config_editor.js

@@ -31,6 +31,23 @@ const bulkDeleteProxyInput = document.getElementById("bulkDeleteProxyInput");
 const resetConfirmModal = document.getElementById("resetConfirmModal");
 const configForm = document.getElementById("configForm"); // Added for frequent use
 
+// Model Helper Modal Elements
+const modelHelperModal = document.getElementById("modelHelperModal");
+const modelHelperTitleElement = document.getElementById("modelHelperTitle");
+const modelHelperSearchInput = document.getElementById(
+  "modelHelperSearchInput"
+);
+const modelHelperListContainer = document.getElementById(
+  "modelHelperListContainer"
+);
+const closeModelHelperModalBtn = document.getElementById(
+  "closeModelHelperModalBtn"
+);
+const cancelModelHelperBtn = document.getElementById("cancelModelHelperBtn");
+
+let cachedModelsList = null;
+let currentModelHelperTarget = null; // { type: 'input'/'array', target: elementOrIdOrKey }
+
 // Modal Control Functions
 function openModal(modalElement) {
   if (modalElement) {
@@ -227,6 +244,7 @@ document.addEventListener("DOMContentLoaded", function () {
       bulkDeleteApiKeyModal,
       proxyModal,
       bulkDeleteProxyModal,
+      modelHelperModal,
     ];
     modals.forEach((modal) => {
       if (event.target === modal) {
@@ -353,6 +371,44 @@ document.addEventListener("DOMContentLoaded", function () {
   }
 
   initializeSensitiveFields(); // Initialize sensitive field handling
+
+  // Model Helper Modal Event Listeners
+  if (closeModelHelperModalBtn) {
+    closeModelHelperModalBtn.addEventListener("click", () =>
+      closeModal(modelHelperModal)
+    );
+  }
+  if (cancelModelHelperBtn) {
+    cancelModelHelperBtn.addEventListener("click", () =>
+      closeModal(modelHelperModal)
+    );
+  }
+  if (modelHelperSearchInput) {
+    modelHelperSearchInput.addEventListener("input", () =>
+      renderModelsInModal()
+    );
+  }
+
+  // Add event listeners to all model helper trigger buttons
+  const modelHelperTriggerBtns = document.querySelectorAll(
+    ".model-helper-trigger-btn"
+  );
+  modelHelperTriggerBtns.forEach((btn) => {
+    btn.addEventListener("click", () => {
+      const targetInputId = btn.dataset.targetInputId;
+      const targetArrayKey = btn.dataset.targetArrayKey;
+
+      if (targetInputId) {
+        currentModelHelperTarget = {
+          type: "input",
+          target: document.getElementById(targetInputId),
+        };
+      } else if (targetArrayKey) {
+        currentModelHelperTarget = { type: "array", targetKey: targetArrayKey };
+      }
+      openModelHelperModal();
+    });
+  });
 }); // <-- DOMContentLoaded end
 
 /**
@@ -1719,3 +1775,140 @@ function addSafetySettingItem(category = "", threshold = "") {
 
   container.appendChild(settingItem);
 }
+
+// --- Model Helper Functions ---
+async function fetchModels() {
+  if (cachedModelsList) {
+    return cachedModelsList;
+  }
+  try {
+    showNotification("正在从 /api/config/ui/models 加载模型列表...", "info");
+    const response = await fetch("/api/config/ui/models");
+    if (!response.ok) {
+      const errorData = await response.text();
+      throw new Error(`HTTP error ${response.status}: ${errorData}`);
+    }
+    const responseData = await response.json(); // Changed variable name to responseData
+    // The backend returns an object like: { object: "list", data: [{id: "m1"}, {id: "m2"}], success: true }
+    if (
+      responseData &&
+      responseData.success &&
+      Array.isArray(responseData.data)
+    ) {
+      cachedModelsList = responseData.data; // Use responseData.data
+      showNotification("模型列表加载成功", "success");
+      return cachedModelsList;
+    } else {
+      console.error("Invalid model list format received:", responseData);
+      throw new Error("模型列表格式无效或请求未成功");
+    }
+  } catch (error) {
+    console.error("加载模型列表失败:", error);
+    showNotification(`加载模型列表失败: ${error.message}`, "error");
+    cachedModelsList = []; // Avoid repeated fetches on error for this session, or set to null to retry
+    return [];
+  }
+}
+
+function renderModelsInModal() {
+  if (!modelHelperListContainer) return;
+  if (!cachedModelsList) {
+    modelHelperListContainer.innerHTML =
+      '<p class="text-gray-400 text-sm italic">模型列表尚未加载。</p>';
+    return;
+  }
+
+  const searchTerm = modelHelperSearchInput.value.toLowerCase();
+  const filteredModels = cachedModelsList.filter((model) =>
+    model.id.toLowerCase().includes(searchTerm)
+  );
+
+  modelHelperListContainer.innerHTML = ""; // Clear previous items
+
+  if (filteredModels.length === 0) {
+    modelHelperListContainer.innerHTML =
+      '<p class="text-gray-400 text-sm italic">未找到匹配的模型。</p>';
+    return;
+  }
+
+  filteredModels.forEach((model) => {
+    const modelItemElement = document.createElement("button");
+    modelItemElement.type = "button";
+    modelItemElement.textContent = model.id;
+    modelItemElement.className =
+      "block w-full text-left px-4 py-2 rounded-md hover:bg-violet-700 focus:bg-violet-700 focus:outline-none transition-colors text-gray-200";
+    // Add any other classes for styling, e.g., from existing modals or array items
+
+    modelItemElement.addEventListener("click", () =>
+      handleModelSelection(model.id)
+    );
+    modelHelperListContainer.appendChild(modelItemElement);
+  });
+}
+
+async function openModelHelperModal() {
+  if (!currentModelHelperTarget) {
+    console.error("Model helper target not set.");
+    showNotification("无法打开模型助手：目标未设置", "error");
+    return;
+  }
+
+  await fetchModels(); // Ensure models are loaded
+  renderModelsInModal(); // Render them (handles empty/error cases internally)
+
+  if (modelHelperTitleElement) {
+    if (
+      currentModelHelperTarget.type === "input" &&
+      currentModelHelperTarget.target
+    ) {
+      const label = document.querySelector(
+        `label[for="${currentModelHelperTarget.target.id}"]`
+      );
+      modelHelperTitleElement.textContent = label
+        ? `为 "${label.textContent.trim()}" 选择模型`
+        : "选择模型";
+    } else if (currentModelHelperTarget.type === "array") {
+      modelHelperTitleElement.textContent = `为 ${currentModelHelperTarget.targetKey} 添加模型`;
+    } else {
+      modelHelperTitleElement.textContent = "选择模型";
+    }
+  }
+  if (modelHelperSearchInput) modelHelperSearchInput.value = ""; // Clear search on open
+  if (modelHelperModal) openModal(modelHelperModal);
+}
+
+function handleModelSelection(selectedModelId) {
+  if (!currentModelHelperTarget) return;
+
+  if (
+    currentModelHelperTarget.type === "input" &&
+    currentModelHelperTarget.target
+  ) {
+    const inputElement = currentModelHelperTarget.target;
+    inputElement.value = selectedModelId;
+    // If the input is a sensitive field, dispatch focusout to trigger masking behavior if needed
+    if (inputElement.classList.contains(SENSITIVE_INPUT_CLASS)) {
+      const event = new Event("focusout", { bubbles: true, cancelable: true });
+      inputElement.dispatchEvent(event);
+    }
+    // Dispatch input event for any other listeners
+    inputElement.dispatchEvent(new Event("input", { bubbles: true }));
+  } else if (
+    currentModelHelperTarget.type === "array" &&
+    currentModelHelperTarget.targetKey
+  ) {
+    const modelId = addArrayItemWithValue(
+      currentModelHelperTarget.targetKey,
+      selectedModelId
+    );
+    if (currentModelHelperTarget.targetKey === "THINKING_MODELS" && modelId) {
+      // Automatically add corresponding budget map item with default budget 0
+      createAndAppendBudgetMapItem(selectedModelId, 0, modelId);
+    }
+  }
+
+  if (modelHelperModal) closeModal(modelHelperModal);
+  currentModelHelperTarget = null; // Reset target
+}
+
+// -- End Model Helper Functions --