fix(uploads): store images in R2 so the Worker can boot - #4

The bug

src/server/uploads.ts stored uploads on the local filesystem with node:fs, and resolved its uploads directory at module scope:

const __dirname = dirname(fileURLToPath(import.meta.url));
const UPLOADS_DIR = join(__dirname, "..", "..", "uploads");
mkdirSync(UPLOADS_DIR, { recursive: true });

On Workers import.meta.url is undefined, so fileURLToPath throws while the module is still being imported. The failure happens before any handler is registered, so the Worker never starts and every route is dead, not just uploads.

Reproduced on a clean checkout with wrangler dev:

✘ [ERROR] service core:user:open-design: Uncaught TypeError:
 The "path" argument must be of type string or an instance of URL. Received undefined
 at fileURLToPath (node-internal:internal_url:155:15)
 MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start.

The fix

Use the R2-backed uploads.ts that the other templates in this family already ship (byte-identical to the one in OpenCMS and OpenFrame), bind the bucket once in middleware ahead of the routes, and declare the binding in wrangler.toml.

• src/server/uploads.ts now talks to R2Bucket instead of fs
• src/server/index.ts calls initUploads(c.env.UPLOADS) in an app.use("*") registered before the routes, so it runs first
• wrangler.toml gains the UPLOADS R2 binding
• README pointed at a stale port and at the old on-disk paths

Verification

Against a local wrangler dev:

vite build succeeds. tsc --noEmit is unchanged from before this branch (the repo has never carried Cloudflare worker types, so D1Database and R2Bucket do not resolve; adding @cloudflare/workers-types globally overrides the DOM fetch typings and breaks the client, so that is left for a separate change).