docs(web): document Phase 0 deployment state

Record each site's custom domain, CF Pages project, and canonical
*.pages.dev URL. Note that the apex wheels.dev is still served by
the CFWheels wheels.dev app and cutover is deferred to Phase 4.
Also adds .wrangler/ (at repo root) to .gitignore — local wrangler
invocations from the wheels repo root create it.

Author: bpamiri

web/README.md

@@ -26,5 +26,35 @@ pnpm build          # builds all four sites
 
 ## Deploy
 
-Cloudflare Pages watches this repo and builds each site when files under its
-path change. See the project dashboard for per-site build settings.
+Deploys are driven by `.github/workflows/web-deploy.yml`, a matrix job that
+runs on push to `develop` (production) and on pull requests (preview). Each
+site uploads to its own Cloudflare Pages project via `wrangler pages deploy`.
+Path filters ensure the workflow only runs when `web/**` or the workflow
+file itself changes.
+
+## Deployed environments
+
+| Site    | Custom domain       | Cloudflare Pages project | Canonical Pages URL        |
+| ------- | ------------------- | ------------------------ | -------------------------- |
+| Landing | _(Phase 4 cutover)_ | `wheels-landing`         | `wheels-landing.pages.dev` |
+| Blog    | `blog.wheels.dev`   | `wheels-blog`            | `wheels-blog.pages.dev`    |
+| Guides  | `guides.wheels.dev` | `wheels-guides`          | `wheels-guides.pages.dev`  |
+| API     | `api.wheels.dev`    | `wheels-api`             | `wheels-api.pages.dev`     |
+
+Production deploys (on push to `develop`) update each site's canonical URL
+and corresponding custom domain. PR preview deploys get a unique
+`<hash>.<project>.pages.dev` URL and a persistent branch alias of the form
+`<slugified-branch>.<project>.pages.dev`.
+
+The apex domain (`wheels.dev`) continues to serve the CFWheels wheels.dev
+app until Phase 4 of the static-site migration. The `wheels-landing`
+project exists and deploys on every push, but no custom domain is attached
+yet — preview via the `*.pages.dev` URL.
+
+## CI secrets required
+
+The deploy workflow needs two repo secrets (see
+`.github/workflows/web-deploy.yml`):
+
+- `CLOUDFLARE_API_TOKEN` — Pages:Edit on the wheels.dev CF account
+- `CLOUDFLARE_ACCOUNT_ID` — `511d04f367103ec276d875ab41a24dea`