feat(hosting): add import-map endpoint with CDN caching

- Move import-map config to hosting/base as single source of truth
- Create /importmap.json endpoint with CORS and caching headers
- Deploy config as code for fast response (no KV lookup)
- Cache-Control: 1hr browser, 24hr CDN

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jchris

hosting/pkg/src/endpoints/import-map.ts

@@ -8,7 +8,7 @@ interface Bindings {
 const app = new Hono<{ Bindings: Bindings }>();
 
 // Serve import map with caching
-app.get("/import-map.json", async (c: Context) => {
+app.get("/importmap.json", async (c: Context) => {
   const importMap = getImportMapJson();
 
   return new Response(importMap, {