Serve the built SPA from the PHP image; drop the web container

The Dockerfile is now multi-stage: a Node stage runs `npm run build`, and the
PHP/Apache stage copies the result into public/. Apache + public/.htaccess route
/api* to the Slim front controller, serve real files, and fall back to
index.html for client-side routes.

docker-compose.yml loses the `web` service, its volume, and the source
bind-mount -- the image is the artifact now (rebuild to pick up changes).
Frontend dev moves to `npm run dev` on the host; APP_URL defaults to :8080 since
the one container serves both halves.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/vite.config.ts

@@ -2,8 +2,8 @@ import vue from '@vitejs/plugin-vue'
 import { defineConfig } from 'vite'
 import { VitePWA } from 'vite-plugin-pwa'
 
-// The API the dev server proxies `/api` to. Defaults to the Dockerised API on
-// the host; the compose `web` service overrides it to the internal address.
+// Host-only dev server: proxy `/api` to the Dockerised API published on the
+// host. Override with VITE_PROXY_TARGET if the API runs elsewhere.
 const proxyTarget = process.env.VITE_PROXY_TARGET ?? 'http://localhost:8080'
 
 // https://vite.dev/config/