Initial commit: Bun · Hono · React SPA · Postgres/Drizzle template

The starting point for an app with a React frontend. Same server, env,
database and API skeleton as template-htmx — the two differ only in what is
served at / — with a React 19 SPA, Tailwind v4 and shadcn/ui on top.

Carried from a working project rather than designed in the abstract, and
carrying the lessons that cost it time:

- The dev script states NODE_ENV=development rather than inheriting it. React
  resolves its runtime against NODE_ENV: Bun emits jsxDEV() in development
  and React's production jsx-dev-runtime defines jsxDEV as void 0. Inherit
  production while transforming for development and the app dies at first
  paint. Verified: the dev bundle resolves the development runtime and
  contains no void-0 stub.
- Asset URLs in components are relative and <base href="/"> is in the HTML,
  so a path-prefix proxy can rewrite one attribute and every asset follows. A
  test enforces it.
- Routing is in the hash, because the app may be mounted under a prefix it
  only learns at runtime and a hash means the same thing at either mount.
- index.html holds __PUBLIC_URL__ and gen-index.ts substitutes it, because
  Bun's HTML bundler fails the build on a root-relative favicon href.
- APP_ENV failing closed, env files before the ambient environment, the
  database enforced by name, one Postgres client per process — as in the
  htmx template.

The database has no tables. The App is a shell with one tab and no features,
named as a placeholder. Renaming `app` is the first step and the README lists
every place it appears.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.env.example

@@ -0,0 +1,12 @@
+# Copy to .env and adjust. Production uses .env.production.local, which wins over this file.
+
+# The dev server's port.
+BUN_PORT=3000
+
+# The absolute base URL this site is served from. Must be the public https origin in production:
+# a loopback address means the reader's own machine, and mobile clients refuse cleartext silently.
+PUBLIC_URL=http://localhost:3000
+
+# Development and test connect here. Production uses POSTGRES_URL from .env.production.local,
+# and the pairing is enforced — a dev process cannot reach the production database.
+POSTGRES_URL_DEV=postgresql://postgres:PASSWORD@127.0.0.1:5432/app_dev