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

packages/coding-agent/examples/extensions/pi-dosbox/index.ts

@@ -0,0 +1,44 @@
+/**
+ * DOSBox extension for pi
+ *
+ * Usage: pi --extension ./examples/extensions/pi-dosbox
+ * Command: /dosbox [bundle.jsdos]
+ */
+
+import { readFile } from "node:fs/promises";
+import { resolve } from "node:path";
+import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
+import { DosboxComponent } from "./src/dosbox-component.js";
+
+export default function (pi: ExtensionAPI) {
+	pi.registerCommand("dosbox", {
+		description: "Run DOSBox emulator",
+
+		handler: async (args, ctx) => {
+			if (!ctx.hasUI) {
+				ctx.ui.notify("DOSBox requires interactive mode", "error");
+				return;
+			}
+
+			const bundlePath = args?.trim();
+			let bundleData: Uint8Array | undefined;
+			if (bundlePath) {
+				try {
+					const resolvedPath = resolve(ctx.cwd, bundlePath);
+					bundleData = await readFile(resolvedPath);
+				} catch (error) {
+					ctx.ui.notify(
+						`Failed to load bundle: ${error instanceof Error ? error.message : String(error)}`,
+						"error",
+					);
+					return;
+				}
+			}
+
+			await ctx.ui.custom((tui, theme, _kb, done) => {
+				const fallbackColor = (s: string) => theme.fg("warning", s);
+				return new DosboxComponent(tui, fallbackColor, () => done(undefined), bundleData);
+			});
+		},
+	});
+}