feat: CodePilot - desktop GUI for Claude Code

Full-featured desktop application built with Next.js + Electron:
- Streaming chat with Claude Code via Agent SDK
- Session management with SQLite persistence
- Project file tree and file preview
- MCP server and custom skills management
- Permission controls with Code/Plan/Ask modes
- Dark/light theme, token tracking
- macOS DMG packaging with electron-builder

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/plugins/ConfigEditor.tsx

@@ -0,0 +1,63 @@
+'use client';
+
+import { useState, useEffect } from 'react';
+import { Textarea } from '@/components/ui/textarea';
+import { Button } from '@/components/ui/button';
+import { Label } from '@/components/ui/label';
+
+interface ConfigEditorProps {
+  value: string;
+  onSave: (value: string) => void;
+  label?: string;
+}
+
+export function ConfigEditor({ value, onSave, label }: ConfigEditorProps) {
+  const [text, setText] = useState(value);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => { setText(value); }, [value]);
+
+  function handleSave() {
+    try {
+      JSON.parse(text);
+      setError(null);
+      onSave(text);
+    } catch (e) {
+      setError(e instanceof Error ? e.message : 'Invalid JSON');
+    }
+  }
+
+  function handleFormat() {
+    try {
+      const parsed = JSON.parse(text);
+      setText(JSON.stringify(parsed, null, 2));
+      setError(null);
+    } catch (e) {
+      setError(e instanceof Error ? e.message : 'Invalid JSON');
+    }
+  }
+
+  return (
+    <div className="space-y-2">
+      {label && <Label>{label}</Label>}
+      <Textarea
+        value={text}
+        onChange={(e) => {
+          setText(e.target.value);
+          setError(null);
+        }}
+        className="font-mono text-sm min-h-[200px]"
+        placeholder="{}"
+      />
+      {error && <p className="text-xs text-destructive">{error}</p>}
+      <div className="flex gap-2">
+        <Button size="sm" onClick={handleSave}>
+          Save
+        </Button>
+        <Button size="sm" variant="outline" onClick={handleFormat}>
+          Format
+        </Button>
+      </div>
+    </div>
+  );
+}