feat(codex): add default model field to provider form

Expose the top-level `model` key of config.toml as an editable field in
the Codex provider form, so users can switch to newly released models
(e.g. gpt-5.6) without waiting for a preset update — preset updates only
affect newly added providers, existing ones keep their saved TOML.

The field syncs bidirectionally with the TOML editor (mirroring the
base-URL pattern), suggests models from the mapping catalog plus the
provider's /models endpoint, and offers a one-click "add to mapping"
action when the value is outside a non-empty catalog. Hidden for
official providers.

Details:

- Save-time catalog sync now only backfills the first mapping row into
  the top-level model when the field was left empty, so the explicit
  field wins over the implicit row-0 sync
- Escape model names (and base_url) with TOML basic-string escaping and
  strip control characters from field input: /models ids are remote
  data and unescaped interpolation could inject config.toml lines
  (e.g. a forged [mcp_servers.*] command)
- The strict model-line matcher now recognizes escaped output, empty
  strings and single-quoted literals, keeping extract/set round-trips
  stable; deliberately no key-only loose matching (it would misfire on
  assignment-looking text inside multiline strings)
- Invalidate the fetched model list whenever the request identity
  changes (base URL, full-URL toggle, API key, custom UA) and discard
  in-flight responses via a sequence guard, so the dropdown never shows
  a previous provider's models
- i18n for zh/en/ja/zh-TW

src/components/providers/forms/CodexFormFields.tsx

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useRef, useState } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { FormLabel } from "@/components/ui/form";
@@ -70,6 +70,10 @@ interface CodexFormFieldsProps {
   autoSelect: boolean;
   onAutoSelectChange: (checked: boolean) => void;
 
+  // Default model (config.toml top-level `model`)
+  codexModel?: string;
+  onModelChange?: (model: string) => void;
+
   // API Format
   // Note: wire_api is always "responses" for Codex; apiFormat controls proxy-layer conversion
   apiFormat: CodexApiFormat;
@@ -166,6 +170,8 @@ export function CodexFormFields({
   onCustomEndpointsChange,
   autoSelect,
   onAutoSelectChange,
+  codexModel = "",
+  onModelChange,
   apiFormat,
   onApiFormatChange,
   anthropicAuthField,
@@ -190,6 +196,15 @@ export function CodexFormFields({
 
   const [fetchedModels, setFetchedModels] = useState<FetchedModel[]>([]);
   const [isFetchingModels, setIsFetchingModels] = useState(false);
+  // 拉取请求序号：请求身份（Base URL / 完整地址开关 / API Key / 自定义 UA）
+  // 一变即自增，清空旧列表并作废在途响应——/models 结果可能按 Key 的模型
+  // 授权返回，换号后残留旧列表会误导选择
+  const fetchModelsSeqRef = useRef(0);
+
+  useEffect(() => {
+    fetchModelsSeqRef.current += 1;
+    setFetchedModels((prev) => (prev.length === 0 ? prev : []));
+  }, [codexBaseUrl, isFullUrl, codexApiKey, customUserAgent]);
   // 思考能力随 Chat 格式显示（仅 Chat Completions 转换路径用得上）；模型映射常驻
   //（填了才生成 catalog）。两者都已与「路由接管」概念解耦。
   const isChatFormat = apiFormat === "openai_chat";
@@ -290,6 +305,7 @@ export function CodexFormFields({
       });
       return;
     }
+    const seq = ++fetchModelsSeqRef.current;
     setIsFetchingModels(true);
     fetchModelsForConfig(
       codexBaseUrl,
@@ -299,6 +315,7 @@ export function CodexFormFields({
       customUserAgent,
     )
       .then((models) => {
+        if (seq !== fetchModelsSeqRef.current) return;
         setFetchedModels(models);
         if (models.length === 0) {
           toast.info(t("providerForm.fetchModelsEmpty"));
@@ -309,6 +326,7 @@ export function CodexFormFields({
         }
       })
       .catch((err) => {
+        if (seq !== fetchModelsSeqRef.current) return;
         console.warn("[ModelFetch] Failed:", err);
         showFetchModelsError(err, t);
       })
@@ -333,6 +351,47 @@ export function CodexFormFields({
     setCatalogRows((current) => current.filter((_, i) => i !== index));
   }, []);
 
+  // 默认模型下拉建议 = 模型映射的"实际请求模型"列 ∪ 拉取到的 /models 列表
+  const defaultModelSuggestions = useMemo<FetchedModel[]>(() => {
+    const seen = new Set<string>();
+    const suggestions: FetchedModel[] = [];
+    for (const row of catalogRows) {
+      const id = row.model.trim();
+      if (!id || seen.has(id)) continue;
+      seen.add(id);
+      suggestions.push({
+        id,
+        ownedBy: t("codexConfig.modelMappingTitle", {
+          defaultValue: "模型映射",
+        }),
+      });
+    }
+    for (const model of fetchedModels) {
+      if (seen.has(model.id)) continue;
+      seen.add(model.id);
+      suggestions.push(model);
+    }
+    return suggestions;
+  }, [catalogRows, fetchedModels, t]);
+
+  // 填了映射时才提示"默认模型不在映射中"（无映射的供应商本来就直接请求任意模型名）
+  const trimmedDefaultModel = codexModel.trim();
+  const isDefaultModelOutsideCatalog =
+    catalogRows.length > 0 &&
+    !!trimmedDefaultModel &&
+    !catalogRows.some((row) => row.model.trim() === trimmedDefaultModel);
+
+  const handleAddDefaultModelToCatalog = useCallback(() => {
+    if (!onCatalogModelsChange || !trimmedDefaultModel) return;
+    setCatalogRows((current) => [
+      ...current,
+      createCatalogRow({
+        model: trimmedDefaultModel,
+        displayName: trimmedDefaultModel,
+      }),
+    ]);
+  }, [onCatalogModelsChange, trimmedDefaultModel]);
+
   const renderCatalogActionButtons = (onAdd: () => void, addLabel: string) => (
     <div className="flex gap-1">
       <Button
@@ -402,6 +461,73 @@ export function CodexFormFields({
         />
       )}
 
+      {/* 默认模型 —— config.toml 顶层 model，Codex 启动时默认请求的模型。
+          实时写回 TOML；留空则删行（有映射时保存回退为映射第一行）。 */}
+      {category !== "official" && onModelChange && (
+        <div className="space-y-1.5">
+          <FormLabel htmlFor="codexDefaultModel">
+            {t("codexConfig.defaultModelLabel", { defaultValue: "默认模型" })}
+          </FormLabel>
+          <div className="flex gap-1">
+            <Input
+              id="codexDefaultModel"
+              value={codexModel}
+              onChange={(event) => onModelChange(event.target.value)}
+              placeholder={t("codexConfig.defaultModelPlaceholder", {
+                defaultValue: "例如: gpt-5.6",
+              })}
+              className="flex-1"
+            />
+            <Button
+              type="button"
+              variant="outline"
+              size="icon"
+              onClick={handleFetchModels}
+              disabled={isFetchingModels}
+              className="shrink-0"
+              title={t("providerForm.fetchModels")}
+            >
+              {isFetchingModels ? (
+                <Loader2 className="h-4 w-4 animate-spin" />
+              ) : (
+                <Download className="h-4 w-4" />
+              )}
+            </Button>
+            {defaultModelSuggestions.length > 0 && (
+              <ModelDropdown
+                models={defaultModelSuggestions}
+                onSelect={(id) => onModelChange(id)}
+              />
+            )}
+          </div>
+          <p className="text-xs leading-relaxed text-muted-foreground">
+            {t("codexConfig.defaultModelHint", {
+              defaultValue:
+                "Codex 默认请求的模型，随时可改，无需等待预设更新。留空且配置了模型映射时，默认使用映射第一行。",
+            })}
+          </p>
+          {isDefaultModelOutsideCatalog && (
+            <p className="flex flex-wrap items-center gap-x-2 text-xs leading-relaxed text-muted-foreground">
+              {t("codexConfig.defaultModelNotInCatalog", {
+                defaultValue:
+                  "该模型不在模型映射中，Codex 的 /model 菜单不会列出它（直接请求仍然有效）。",
+              })}
+              <Button
+                type="button"
+                variant="link"
+                size="sm"
+                className="h-auto p-0 text-xs"
+                onClick={handleAddDefaultModelToCatalog}
+              >
+                {t("codexConfig.addToModelMapping", {
+                  defaultValue: "加入映射",
+                })}
+              </Button>
+            </p>
+          )}
+        </div>
+      )}
+
       {/* 高级选项 —— 上游格式/模型映射/思考能力/自定义 UA；预设供应商通常无需展开 */}
       {category !== "official" && (
         <Collapsible

src/components/providers/forms/ProviderForm.tsx

@@ -63,6 +63,7 @@ import {
   codexApiFormatFromWireApi,
   extractCodexWireApi,
   setCodexWireApi,
+  extractCodexModelName,
   setCodexModelName as setCodexModelNameInConfig,
 } from "@/utils/providerConfigUtils";
 import { isNonNegativeDecimalString } from "@/types/usage";
@@ -554,6 +555,7 @@ function ProviderFormFull({
     codexConfig,
     codexApiKey,
     codexBaseUrl,
+    codexModel,
     codexCatalogModels,
     codexAuthError,
     setCodexAuth,
@@ -561,6 +563,7 @@ function ProviderFormFull({
     setCodexCatalogModels,
     handleCodexApiKeyChange,
     handleCodexBaseUrlChange,
+    handleCodexModelChange,
     handleCodexConfigChange: originalHandleCodexConfigChange,
     resetCodexConfig,
   } = useCodexConfigState({ initialData });
@@ -1286,8 +1289,13 @@ function ProviderFormFull({
           category !== "official"
             ? normalizeCodexCatalogModelsForSave(codexCatalogModels)
             : [];
-        // Sync first catalog row's model into config.toml so Codex uses it as default
-        if (normalizedCatalogModels.length > 0) {
+        // The default-model field writes the top-level `model` into the TOML
+        // as the user types; only when it was left empty fall back to the
+        // first catalog row so "fill mapping only" keeps its old behavior.
+        if (
+          normalizedCatalogModels.length > 0 &&
+          !extractCodexModelName(normalizedCodexConfig)
+        ) {
           normalizedCodexConfig = setCodexModelNameInConfig(
             normalizedCodexConfig,
             normalizedCatalogModels[0].model,
@@ -2168,6 +2176,8 @@ function ProviderFormFull({
               }
               autoSelect={endpointAutoSelect}
               onAutoSelectChange={setEndpointAutoSelect}
+              codexModel={codexModel}
+              onModelChange={handleCodexModelChange}
               apiFormat={localCodexApiFormat}
               onApiFormatChange={handleCodexApiFormatChange}
               anthropicAuthField={localCodexAnthropicAuthField}

src/components/providers/forms/hooks/useCodexConfigState.ts

@@ -2,7 +2,9 @@ import { useState, useCallback, useEffect, useRef } from "react";
 import {
   extractCodexBaseUrl,
   extractCodexExperimentalBearerToken,
+  extractCodexModelName,
   setCodexBaseUrl as setCodexBaseUrlInConfig,
+  setCodexModelName as setCodexModelNameInConfig,
   updateCodexExperimentalBearerToken,
 } from "@/utils/providerConfigUtils";
 import { normalizeTomlText } from "@/utils/textNormalization";
@@ -36,12 +38,14 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
   const [codexConfig, setCodexConfigState] = useState("");
   const [codexApiKey, setCodexApiKey] = useState("");
   const [codexBaseUrl, setCodexBaseUrl] = useState("");
+  const [codexModel, setCodexModel] = useState("");
   const [codexCatalogModels, setCodexCatalogModels] = useState<
     CodexCatalogModel[]
   >([]);
   const [codexAuthError, setCodexAuthError] = useState("");
 
   const isUpdatingCodexBaseUrlRef = useRef(false);
+  const isUpdatingCodexModelRef = useRef(false);
 
   // 初始化 Codex 配置（编辑模式）
   useEffect(() => {
@@ -133,6 +137,15 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     setCodexBaseUrl((prev) => (prev === extracted ? prev : extracted));
   }, [codexConfig]);
 
+  // 与 TOML 配置保持默认模型同步（顶层 model 键）
+  useEffect(() => {
+    if (isUpdatingCodexModelRef.current) {
+      return;
+    }
+    const extracted = extractCodexModelName(codexConfig) || "";
+    setCodexModel((prev) => (prev === extracted ? prev : extracted));
+  }, [codexConfig]);
+
   // 获取 API Key（从 auth JSON）
   const getCodexAuthApiKey = useCallback((authString: string): string => {
     try {
@@ -226,6 +239,22 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     [setCodexConfig],
   );
 
+  // 处理默认模型变化（写回 TOML 顶层 model；清空则删掉该行，交回 Codex 内置默认）
+  // 剥控制字符：值可能来自 /models 下拉（远端数据），换行等会破坏单行 TOML 语义
+  const handleCodexModelChange = useCallback(
+    (model: string) => {
+      const sanitized = model.replace(/[\u0000-\u001f\u007f]/g, "").trim();
+      setCodexModel(sanitized);
+
+      isUpdatingCodexModelRef.current = true;
+      setCodexConfig((prev) => setCodexModelNameInConfig(prev, sanitized));
+      setTimeout(() => {
+        isUpdatingCodexModelRef.current = false;
+      }, 0);
+    },
+    [setCodexConfig],
+  );
+
   // 处理 config 变化（同步 Base URL）
   const handleCodexConfigChange = useCallback(
     (value: string) => {
@@ -268,6 +297,7 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     codexConfig,
     codexApiKey,
     codexBaseUrl,
+    codexModel,
     codexCatalogModels,
     codexAuthError,
     setCodexAuth,
@@ -275,6 +305,7 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     setCodexCatalogModels,
     handleCodexApiKeyChange,
     handleCodexBaseUrlChange,
+    handleCodexModelChange,
     handleCodexConfigChange,
     resetCodexConfig,
     getCodexAuthApiKey,