PolyCity v1.0 — full-featured 3D city-builder (Three.js + Vite)

- Procedural island maps, RCI zoning, demand-driven growth
- City-wide power grid with brownouts; wind coastal bonus
- Land value, upgrades, services, pollution, fires & fire spread
- Budget/taxes, happiness, milestones, quest onboarding
- Traffic agents, day/night cycle, adaptive render scale
- Saves: autosave + 3 slots + JSON export/import
- PWA (offline), GitHub Pages/Netlify deploy configs
- Tests: 40-assertion engine suite + headless E2E

public/sw.js

@@ -0,0 +1,38 @@
+/* PolyCity service worker — offline-first app shell */
+const CACHE = 'polycity-v1';
+const PRECACHE = ['./', './index.html', './manifest.webmanifest', './icon.svg', './icon-maskable.svg'];
+
+self.addEventListener('install', (e) => {
+  e.waitUntil(
+    caches.open(CACHE).then((c) => c.addAll(PRECACHE)).then(() => self.skipWaiting())
+  );
+});
+
+self.addEventListener('activate', (e) => {
+  e.waitUntil(
+    caches.keys()
+      .then((keys) => Promise.all(keys.filter((k) => k !== CACHE).map((k) => caches.delete(k))))
+      .then(() => self.clients.claim())
+  );
+});
+
+self.addEventListener('fetch', (e) => {
+  const url = new URL(e.request.url);
+  if (e.request.method !== 'GET' || url.origin !== location.origin) return;
+  // cache-first for hashed assets, network-first for navigations
+  if (url.pathname.includes('/assets/')) {
+    e.respondWith(
+      caches.match(e.request).then((hit) => hit || fetch(e.request).then((res) => {
+        const copy = res.clone();
+        caches.open(CACHE).then((c) => c.put(e.request, copy));
+        return res;
+      }))
+    );
+  } else if (e.request.mode === 'navigate') {
+    e.respondWith(
+      fetch(e.request)
+        .then((res) => { caches.open(CACHE).then((c) => c.put('./index.html', res.clone())); return res; })
+        .catch(() => caches.match('./index.html'))
+    );
+  }
+});