feat: add CI, Docker, auth, typed API client, shiki code blocks, e2e tests

- CI: GitHub Actions (bun 1.3.14, lint/typecheck/test/build/format gates)
- Docker: multi-stage standalone build + .dockerignore (next.config output=standalone)
- Auth: better-auth server (memory adapter, drizzle-swap-ready) + react client
  + /api/auth/[...all] route handler
- API: /api/health + /api/openapi routes, openapi-typescript codegen to
  types/api.ts, typed openapi-fetch client (lib/api, lib/http)
- Shiki: server-side CodeBlock component (escaped HTML)
- E2E: playwright home + health specs on dedicated :3100 (chromium 1243
  installed from GCS after CDN timeout)
- Dev: allow 127.0.0.1/localhost dev origins (HMR for local tooling)

lib/api.ts

@@ -0,0 +1,11 @@
+import createClient from "openapi-fetch";
+import type { paths } from "@/types/api";
+
+export const api = createClient<paths>({
+  baseUrl: "/",
+});
+
+// Typed convenience wrappers for the template's own API routes.
+export const healthApi = {
+  get: () => api.GET("/api/health"),
+};