Can I vibecode Bitly?

Build me a link shortener with click analytics and QR codes to replace Bitly. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, and it runs on my own domain.
- A worker on go.mydomain.com/{slug} reads KV and 302s, writing the click to
  D1 inside ctx.waitUntil so the redirect never waits on the database.
- Slugs are random 6-character base62 by default, but I can set a custom
  back-half, and creating one that already exists fails loudly instead of
  overwriting it.
- Log per click: slug, timestamp, country and city from request.cf,
  device type parsed from the user-agent, and referer.
- Generate a PNG QR code for any link with the qrcode npm package, served at
  /qr/{slug} and cached, so print material points at the same tracked link.
- Optional expiry and a click cap per link · past either, 302 to a fallback
  URL I set instead of returning a 404.
- An /admin page behind one password (wrangler secret) listing links with
  clicks per day, plus top countries and device split per link.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and a warning that these links die with the domain, so use a domain you
  intend to keep renewing.