fix: add bun install to go:generate and packages:bundle to build

- Split go:generate into `bun install` + `bun run build` so deps are
  always available before bundling (fixes build on clean checkout)
- Add `packages: 'bundle'` to Bun.build() so node_modules are resolved
  and bundled into the output (required for marked + highlight.js)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pkg/miniapp/frontend/build.mjs

@@ -15,6 +15,7 @@ const result = await Bun.build({
   target: 'browser',
   format: 'iife',
   sourcemap: 'none',
+  packages: 'bundle',
 });
 
 if (!result.success) {

pkg/miniapp/miniapp.go

@@ -13,6 +13,7 @@ import (
 	"github.com/sipeed/picoclaw/pkg/research"
 )
 
+//go:generate bun install --cwd frontend
 //go:generate bun run --cwd frontend build
 //go:embed static
 var staticFS embed.FS