Add master display UI with audio output management and styling

- Implement main.js for the master display functionality, including WebSocket connection, audio output management, and state handling.
- Create style.css for the master display's visual design, ensuring a cohesive look and feel with a dark theme and responsive layout.
- Integrate device management with a fallback for non-Electron environments, allowing users to select audio outputs.
- Add features for managing favorites, including toggling favorites and filtering by genre.
- Enhance user experience with a responsive favorites grid and drag-to-scroll functionality.

server/stations.js

@@ -3,6 +3,8 @@ import { getDb } from './db/index.js';
 
 function rowToStation(row) {
     if (!row) return null;
+    const imagePath = row.image_path || null;
+    const remote = row.image_url || null;
     return {
         id: row.id,
         uuid: row.uuid,
@@ -12,7 +14,12 @@ function rowToStation(row) {
         country: row.country,
         genres: row.genres ? JSON.parse(row.genres) : [],
         description: row.description,
-        image_url: row.image_url,
+        // image_url remains the remote/source URL (what admins edit).
+        // image_display_url is what UIs should render — prefers the local cache.
+        image_url: remote,
+        image_path: imagePath,
+        image_source: row.image_source || null,
+        image_display_url: imagePath ? `/media/${imagePath}` : remote,
         source: row.source,
         source_ref: row.source_ref,
         category: row.category,