feat(gemini): add config.json editor and common config functionality

Implements dual-editor pattern for Gemini providers, following the Codex architecture:
- Environment variables (.env format) editor
- Extended configuration (config.json) editor with common config support

New Components:
- GeminiConfigSections: Separate sections for env and config editing
- GeminiCommonConfigModal: Modal for editing common config snippets

New Hooks:
- useGeminiConfigState: Manages env/config separation and conversion
  - Converts between .env string format and JSON object
  - Validates JSON config structure
  - Extracts API Key and Base URL from env
- useGeminiCommonConfig: Handles common config snippets
  - Deep merge algorithm for combining configs
  - Remove common config logic for toggling off
  - localStorage persistence for snippets

Features:
- Format buttons for both env and config editors
- Common config toggle with deep merge/remove
- Error validation and display
- Auto-open modal on common config errors

Configuration Structure:
{
  "env": {
    "GOOGLE_GEMINI_BASE_URL": "https://...",
    "GEMINI_API_KEY": "sk-...",
    "GEMINI_MODEL": "gemini-2.5-pro"
  },
  "config": {
    "timeout": 30000,
    "maxRetries": 3
  }
}

This brings Gemini providers to feature parity with Claude and Codex.

src/components/providers/forms/GeminiConfigEditor.tsx

@@ -1,139 +1,76 @@
-import { useTranslation } from "react-i18next";
-import { Label } from "@/components/ui/label";
-import { Wand2 } from "lucide-react";
-import { toast } from "sonner";
+import React, { useState, useEffect } from "react";
+import { GeminiEnvSection, GeminiConfigSection } from "./GeminiConfigSections";
+import { GeminiCommonConfigModal } from "./GeminiCommonConfigModal";
 
 interface GeminiConfigEditorProps {
-  value: string;
-  onChange: (value: string) => void;
+  envValue: string;
+  configValue: string;
+  onEnvChange: (value: string) => void;
+  onConfigChange: (value: string) => void;
+  onEnvBlur?: () => void;
+  useCommonConfig: boolean;
+  onCommonConfigToggle: (checked: boolean) => void;
+  commonConfigSnippet: string;
+  onCommonConfigSnippetChange: (value: string) => void;
+  commonConfigError: string;
+  envError: string;
+  configError: string;
 }
 
-export function GeminiConfigEditor({
-  value,
-  onChange,
-}: GeminiConfigEditorProps) {
-  const { t } = useTranslation();
+const GeminiConfigEditor: React.FC<GeminiConfigEditorProps> = ({
+  envValue,
+  configValue,
+  onEnvChange,
+  onConfigChange,
+  onEnvBlur,
+  useCommonConfig,
+  onCommonConfigToggle,
+  commonConfigSnippet,
+  onCommonConfigSnippetChange,
+  commonConfigError,
+  envError,
+  configError,
+}) => {
+  const [isCommonConfigModalOpen, setIsCommonConfigModalOpen] = useState(false);
 
-  // 将 JSON 格式转换为 .env 格式显示
-  const jsonToEnv = (jsonString: string): string => {
-    try {
-      const config = JSON.parse(jsonString);
-      const env = config?.env || {};
-
-      const lines: string[] = [];
-      if (env.GOOGLE_GEMINI_BASE_URL) {
-        lines.push(`GOOGLE_GEMINI_BASE_URL=${env.GOOGLE_GEMINI_BASE_URL}`);
-      }
-      if (env.GEMINI_API_KEY) {
-        lines.push(`GEMINI_API_KEY=${env.GEMINI_API_KEY}`);
-      }
-      if (env.GEMINI_MODEL) {
-        lines.push(`GEMINI_MODEL=${env.GEMINI_MODEL}`);
-      }
-
-      return lines.join("\n");
-    } catch {
-      return "";
+  // Auto-open common config modal if there's an error
+  useEffect(() => {
+    if (commonConfigError && !isCommonConfigModalOpen) {
+      setIsCommonConfigModalOpen(true);
     }
-  };
-
-  // 将 .env 格式转换为 JSON 格式保存
-  const envToJson = (envString: string): string => {
-    try {
-      const lines = envString.split("\n");
-      const env: Record<string, string> = {};
-
-      lines.forEach((line) => {
-        const trimmed = line.trim();
-        if (!trimmed || trimmed.startsWith("#")) return;
-
-        const equalIndex = trimmed.indexOf("=");
-        if (equalIndex > 0) {
-          const key = trimmed.substring(0, equalIndex).trim();
-          const value = trimmed.substring(equalIndex + 1).trim();
-          env[key] = value;
-        }
-      });
-
-      return JSON.stringify({ env }, null, 2);
-    } catch {
-      return value;
-    }
-  };
-
-  const displayValue = jsonToEnv(value);
-
-  const handleChange = (envString: string) => {
-    const jsonString = envToJson(envString);
-    onChange(jsonString);
-  };
-
-  const handleFormat = () => {
-    if (!value.trim()) return;
-
-    try {
-      // 重新格式化
-      const envString = jsonToEnv(value);
-      const formatted = envString
-        .split("\n")
-        .filter((l) => l.trim())
-        .join("\n");
-      const jsonString = envToJson(formatted);
-      onChange(jsonString);
-      toast.success(t("common.formatSuccess", { defaultValue: "格式化成功" }));
-    } catch (error) {
-      const errorMessage =
-        error instanceof Error ? error.message : String(error);
-      toast.error(
-        t("common.formatError", {
-          defaultValue: "格式化失败：{{error}}",
-          error: errorMessage,
-        }),
-      );
-    }
-  };
+  }, [commonConfigError, isCommonConfigModalOpen]);
 
   return (
-    <div className="space-y-2">
-      <div className="flex items-center justify-between">
-        <Label htmlFor="geminiConfig">
-          {t("provider.geminiConfig", { defaultValue: "Gemini 配置" })}
-        </Label>
-      </div>
-      <textarea
-        id="geminiConfig"
-        value={displayValue}
-        onChange={(e) => handleChange(e.target.value)}
-        placeholder={`GOOGLE_GEMINI_BASE_URL=https://your-api-endpoint.com/
-GEMINI_API_KEY=sk-your-api-key-here
-GEMINI_MODEL=gemini-2.5-pro`}
-        rows={8}
-        className="w-full px-3 py-2 border border-border-default dark:bg-gray-800 dark:text-gray-100 rounded-lg text-sm font-mono focus:outline-none focus:ring-2 focus:ring-blue-500/20 dark:focus:ring-blue-400/20 transition-colors resize-y min-h-[10rem]"
-        autoComplete="off"
-        autoCorrect="off"
-        autoCapitalize="none"
-        spellCheck={false}
-        lang="en"
-        inputMode="text"
-        data-gramm="false"
-        data-gramm_editor="false"
-        data-enable-grammarly="false"
+    <div className="space-y-6">
+      {/* Env Section */}
+      <GeminiEnvSection
+        value={envValue}
+        onChange={onEnvChange}
+        onBlur={onEnvBlur}
+        error={envError}
+      />
+
+      {/* Config JSON Section */}
+      <GeminiConfigSection
+        value={configValue}
+        onChange={onConfigChange}
+        useCommonConfig={useCommonConfig}
+        onCommonConfigToggle={onCommonConfigToggle}
+        onEditCommonConfig={() => setIsCommonConfigModalOpen(true)}
+        commonConfigError={commonConfigError}
+        configError={configError}
+      />
+
+      {/* Common Config Modal */}
+      <GeminiCommonConfigModal
+        isOpen={isCommonConfigModalOpen}
+        onClose={() => setIsCommonConfigModalOpen(false)}
+        value={commonConfigSnippet}
+        onChange={onCommonConfigSnippetChange}
+        error={commonConfigError}
       />
-      <div className="flex items-center justify-between">
-        <button
-          type="button"
-          onClick={handleFormat}
-          className="inline-flex items-center gap-1.5 px-3 py-1.5 text-xs font-medium text-gray-700 dark:text-gray-300 hover:text-blue-600 dark:hover:text-blue-400 transition-colors"
-        >
-          <Wand2 className="w-3.5 h-3.5" />
-          {t("common.format", { defaultValue: "格式化" })}
-        </button>
-        <p className="text-xs text-muted-foreground">
-          {t("provider.geminiConfigHint", {
-            defaultValue: "使用 .env 格式配置 Gemini",
-          })}
-        </p>
-      </div>
     </div>
   );
-}
+};
+
+export default GeminiConfigEditor;