vercel.json rewrites every route to /index.html on a static multi-page site #12

Describe the bug

`vercel.json` has a catch-all SPA rewrite:

```json
"rewrites": [
{ "source": "/(.*)", "destination": "/index.html" }
]
```

This site is a static multi-page Astro build that emits real per-route HTML (~215 pages) — not a single-page app. A catch-all rewrite to `/index.html` is the wrong behavior here.

Separately, the `www` → apex redirect is written as a literal path pattern (`"source": "www.ephbaum.dev/(.*)"`), which matches against the request path, not the hostname, so it likely never actually fires.

Expected behavior

No SPA rewrite. The `www` redirect should match on host (via `"has": [{ "type": "host", "value": "www.ephbaum.dev" }]`) so it actually triggers.

Additional context

Fixed in #9.