chore: monorepo scaffold, CI, MIT license

Bun workspaces (server/web/shared), typecheck+test gates, Gitea CI.
Refs PAI-90.

server/src/index.ts

@@ -0,0 +1,6 @@
+import { Hono } from "hono";
+
+const app = new Hono();
+app.get("/api/health", (c) => c.json({ ok: true }));
+
+export default { port: Number(process.env.PORT ?? 3000), fetch: app.fetch };