Dev workflow: network-bound vite dev + documented hot-reload loop

- 'npm run dev' now binds the network (vite dev --host) so the HMR dev server is
  reachable from another machine.
- README documents the two-terminal loop (serve --reload + npm run dev via the
  /api proxy), so iterating no longer needs build + restart + hard-refresh.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -113,6 +113,22 @@ Endpoints:
 The ingestion CLI stays pure-stdlib; only the `web` extra pulls in FastAPI/uvicorn,
 so the two halves can be deployed and upgraded independently.
 
+### Development (hot-reload, no rebuild dance)
+
+Two terminals, and you stop having to `npm run build` + restart + hard-refresh:
+
+```bash
+# 1. API with auto-reload on backend code changes
+python3 -m goodnews serve --host 0.0.0.0 --port 8000 --reload
+
+# 2. Vite dev server with hot module reload (proxies /api -> :8000)
+cd frontend && npm run dev      # serves on http://<host>:5173
+```
+
+Visit **:5173** while developing — frontend edits hot-reload instantly, and the
+`--reload` API restarts itself on backend edits. Only build (`npm run build`) +
+serve on `:8000` when you want to check the production-served form.
+
 ### Frontend
 
 The site is a SvelteKit static SPA in `frontend/` (calm editorial design, mood-mode