feat: add bun-fullstack agent and update skills

.opencode/skills/tech-stack/elysiajs/examples/map-response.ts

@@ -0,0 +1,15 @@
+import { Elysia } from 'elysia'
+
+const prettyJson = new Elysia()
+	.mapResponse(({ response }) => {
+		if (response instanceof Object)
+			return new Response(JSON.stringify(response, null, 4))
+	})
+	.as('scoped')
+
+new Elysia()
+	.use(prettyJson)
+	.get('/', () => ({
+		hello: 'world'
+	}))
+	.listen(3000)