docker updates.

src/player/player-page.script.html

@@ -1,6 +1,17 @@
 <script>
-  const slug = {{SLUG_JSON}};
-  const initialData = {{INITIAL_DATA_JSON}};
+  function parseTemplateJson(templateValue, fallbackValue) {
+    if (typeof templateValue !== 'string' || /^\s*\{\{.*\}\}\s*$/.test(templateValue)) {
+      return fallbackValue;
+    }
+    try {
+      return JSON.parse(templateValue);
+    } catch (_error) {
+      return fallbackValue;
+    }
+  }
+
+  const slug = parseTemplateJson('{{SLUG_JSON}}', '');
+  const initialData = parseTemplateJson('{{INITIAL_DATA_JSON}}', {});
   const app = document.getElementById('app');
   let slides = Array.isArray(initialData && initialData.slides) ? initialData.slides.map(normalizeSlide) : [];
   let currentPlaylistSignature = '';
@@ -31,7 +42,7 @@
   let slideExpiresAt = null;
   const slideFadeDurationMs = 560;
   const commandSocketPath = '/ws/screens/' + encodeURIComponent(slug);
-  const commandClientStorageKey = 'digital-signage-player-client-id:' + slug;
+  const commandClientStorageKey = 'pulse-signage-player-client-id:' + slug;
 
   // Escape text before inserting it into HTML.
   function escapeHtml(value) {