feat: add beacon nexus portal slice (#167)

js/utils.js

@@ -193,6 +193,73 @@ function spellf(n) {
     return parts.join(' ') || 'zero';
 }
 
+// === PORTAL HELPERS ===
+function getBeaconPortalId() {
+    try {
+        const search = (typeof window !== 'undefined' && window.location && typeof window.location.search === 'string')
+            ? window.location.search.replace(/^\?/, '')
+            : '';
+        if (!search) return '';
+        for (const chunk of search.split('&')) {
+            if (!chunk) continue;
+            const [rawKey, rawValue = ''] = chunk.split('=');
+            if (decodeURIComponent(rawKey || '') === 'portal') {
+                return decodeURIComponent(rawValue.replace(/\+/g, ' ')).trim();
+            }
+        }
+    } catch (e) {}
+    return '';
+}
+
+function isBeaconPortalEmbed() {
+    try {
+        const search = (typeof window !== 'undefined' && window.location && typeof window.location.search === 'string')
+            ? window.location.search.replace(/^\?/, '')
+            : '';
+        if (!search) return false;
+        for (const chunk of search.split('&')) {
+            if (!chunk) continue;
+            const [rawKey, rawValue = ''] = chunk.split('=');
+            if (decodeURIComponent(rawKey || '') === 'embedded') {
+                return decodeURIComponent(rawValue.replace(/\+/g, ' ')) === '1';
+            }
+        }
+    } catch (e) {}
+    return false;
+}
+
+function getBeaconScopedStorageKey(baseKey) {
+    const portalId = getBeaconPortalId();
+    return portalId ? `${baseKey}:${portalId}` : baseKey;
+}
+
+function getBeaconSaveKey() {
+    return getBeaconScopedStorageKey('the-beacon-v2');
+}
+
+function clearBeaconSaveAndReload() {
+    try {
+        if (typeof localStorage !== 'undefined') {
+            localStorage.removeItem(getBeaconSaveKey());
+        }
+    } catch (e) {}
+    if (typeof location !== 'undefined' && location && typeof location.reload === 'function') {
+        location.reload();
+    }
+}
+
+function applyPortalMode() {
+    if (typeof document === 'undefined' || !document.body) return;
+    const portalId = getBeaconPortalId();
+    if (portalId) {
+        document.body.setAttribute('data-portal-id', portalId);
+        if (document.body.dataset) document.body.dataset.portalId = portalId;
+    }
+    if (isBeaconPortalEmbed()) {
+        document.body.classList.add('portal-embed');
+    }
+}
+
 // NOTE: exportSave() and importSave() are defined in render.js (file-based).
 // The clipboard/prompt versions that were here were dead code — render.js
 // loads after utils.js and overrides them. Removed to avoid confusion.