feat(coding-agent): add DOSBox terminal extension

- Render DOSBox framebuffer as images in terminal via emulators package
- Support keyboard input with js-dos key codes
- Push Kitty enhanced mode for proper key press/release events
- Standalone app (npm start) and pi extension entry point
- Exit with Ctrl+Q

package.json

@@ -5,7 +5,8 @@
 	"workspaces": [
 		"packages/*",
 		"packages/web-ui/example",
-		"packages/coding-agent/examples/extensions/with-deps"
+		"packages/coding-agent/examples/extensions/with-deps",
+		"packages/coding-agent/examples/extensions/pi-dosbox"
 	],
 	"scripts": {
 		"clean": "npm run clean --workspaces",