chore: bump version to 0.4.0 and fix Linux desktop entry format

- Bump version to 0.4.0 for new release
- Fix electron-builder linux.desktop config to use entry sub-object
  (required by electron-builder 26.7.0)

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

electron-builder.yml

@@ -61,10 +61,11 @@ linux:
   category: Development
   artifactName: "${productName}-${version}-${arch}.${ext}"
   desktop:
-    Name: CodePilot
-    Comment: A native desktop GUI for Claude Code
-    Categories: Development;IDE;
-    StartupWMClass: codepilot
+    entry:
+      Name: CodePilot
+      Comment: A native desktop GUI for Claude Code
+      Categories: Development;IDE;
+      StartupWMClass: codepilot
   target:
     - target: AppImage
       arch: [x64, arm64]

package.json

@@ -1,6 +1,6 @@
 {
   "name": "codepilot",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "private": true,
   "main": "dist-electron/main.js",
   "scripts": {