refactor(vscode-ide-companion): simplify ACP connection and cleanup configurations

- Remove .claude from .gitignore
- Update CSS file path in eslint config
- Simplify VS Code extension title
- Remove unused keybinding for openChat command
- Delete unused auth constants file
- Simplify ACP connection by removing backend parameter
- Move authMethod to acpTypes
- Restrict ACP backend to Qwen only
- Remove backend property from connection state
- Minor formatting update in webview index.tsx

eslint.config.js

@@ -120,7 +120,7 @@ export default tseslint.config(
             '**/generated/**',
             './styles/tailwind.css',
             './styles/App.css',
-            './styles/ClaudeCodeStyles.css'
+            './styles/style.css'
           ],
         },
       ],