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/scripts/download-images.js

@@ -0,0 +1,65 @@
+// Backfill cover-art for every station missing a local image.
+//
+//   node server/scripts/download-images.js          # only stations missing a local file
+//   node server/scripts/download-images.js --all    # re-download even cached stations
+//   node server/scripts/download-images.js --no-scrape  # skip homepage scrape fallback
+//
+// Strategy per station:
+//   1. Try downloading the existing image_url.
+//   2. On failure (404, HTML, dead host, ...), call scrapeIcon() to find a
+//      fresh icon from Radio-Browser / the station homepage, persist the new
+//      URL, and try again.
+//
+// Safe to re-run.
+
+import 'dotenv/config';
+import { initDb } from '../db/index.js';
+import { listStations, updateStation } from '../stations.js';
+import { saveStationImageFromUrl, ensureImageDirs } from '../media/images.js';
+import { scrapeIcon } from '../sources/iconScraper.js';
+
+const FORCE = process.argv.includes('--all');
+const NO_SCRAPE = process.argv.includes('--no-scrape');
+const CONCURRENCY = 4;
+
+initDb(process.env.DB_PATH || './data/db/oradio.sqlite');
+ensureImageDirs();
+
+const all = listStations({ enabled: null });
+const todo = all.filter((s) => FORCE || !s.image_path);
+console.log(`[images] ${todo.length} of ${all.length} stations to fetch (force=${FORCE}, scrape=${!NO_SCRAPE})`);
+
+let i = 0, ok = 0, scraped = 0, fail = 0;
+async function worker() {
+    while (i < todo.length) {
+        const idx = i++;
+        const s = todo[idx];
+        const label = `[${idx + 1}/${todo.length}] ${s.name}`;
+
+        // 1. Try the existing remote URL.
+        let rel = s.image_url
+            ? await saveStationImageFromUrl(s.id, s.image_url, { source: s.image_source || 'remote' })
+            : null;
+
+        // 2. Fallback: scrape a fresh icon from the homepage / Radio-Browser.
+        if (!rel && !NO_SCRAPE) {
+            const found = await scrapeIcon(s);
+            if (found && found !== s.image_url) {
+                updateStation(s.id, { image_url: found });
+                rel = await saveStationImageFromUrl(s.id, found, { source: 'scraped' });
+                if (rel) scraped++;
+            }
+        }
+
+        if (rel) {
+            ok++;
+            console.log(`  ${label} -> ${rel}`);
+        } else {
+            fail++;
+            console.log(`  ${label} ✗ (${s.image_url || 'no url'})`);
+        }
+    }
+}
+await Promise.all(Array.from({ length: CONCURRENCY }, worker));
+console.log(`[images] done. ok=${ok} (scraped=${scraped}) fail=${fail}`);
+process.exit(0);