fix: break native boot reload loops before they trap the app

public/boot-guard.js

@@ -9,6 +9,51 @@
 (function () {
   var shown = false;
 
+  // Reload-loop breaker. A stale app-shell worker can reload before the boot
+  // guard's 12s error panel is ever shown. After three loads inside one minute,
+  // clear the shell cache/worker once and reload into a clean shell.
+  try {
+    var ATTEMPT_KEY = 'skatespots:boot-attempts';
+    var now = Date.now();
+    var attempts = { count: 0, at: now };
+    try {
+      var stored = JSON.parse(sessionStorage.getItem(ATTEMPT_KEY) || 'null');
+      if (stored && typeof stored.at === 'number' && now - stored.at < 60000) {
+        attempts.count = Number(stored.count) || 0;
+      }
+    } catch (e) {}
+    attempts.count += 1;
+    attempts.at = now;
+    try { sessionStorage.setItem(ATTEMPT_KEY, JSON.stringify(attempts)); } catch (e) {}
+    if (attempts.count >= 3) {
+      try { sessionStorage.removeItem(ATTEMPT_KEY); } catch (e) {}
+      var finished = false;
+      var finish = function () {
+        if (finished) return;
+        finished = true;
+        location.reload();
+      };
+      var jobs = [];
+      try {
+        if ('serviceWorker' in navigator) {
+          jobs.push(navigator.serviceWorker.getRegistrations().then(function (regs) {
+            regs.forEach(function (reg) { try { reg.unregister(); } catch (e) {} });
+          }).catch(function () {}));
+        }
+        if (window.caches) {
+          jobs.push(window.caches.keys().then(function (keys) {
+            return Promise.all(keys.filter(function (key) { return key.indexOf('skate-spots-shell-') === 0; })
+              .map(function (key) { return window.caches.delete(key).catch(function () {}); }));
+          }).catch(function () {}));
+        }
+      } catch (e) {}
+      if (jobs.length) Promise.all(jobs).then(finish).catch(finish);
+      else finish();
+      setTimeout(finish, 1000);
+      return;
+    }
+  } catch (e) { /* best effort */ }
+
   // Native WebViews can keep a service worker from an older build forever.
   // That worker can serve a stale index.html whose hashed chunks no longer
   // exist, producing a white/black reload loop. The native shell is served from