feat: Add cover art support and auto-migration

- Extract cover art from MP3s during upload
- Display cover art in game result screens (win/loss)
- Add coverImage field to Song model
- Add migration script to backfill covers for existing songs
- Configure Docker to run migration script on startup

scripts/migrate-covers.mjs

@@ -0,0 +1,66 @@
+import { PrismaClient } from '@prisma/client';
+import { parseBuffer } from 'music-metadata';
+import { readFile, writeFile } from 'fs/promises';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// Adjust path to reach root from scripts/
+const prisma = new PrismaClient();
+
+async function migrate() {
+    console.log('Starting cover art migration...');
+
+    try {
+        // Find songs without cover image
+        const songs = await prisma.song.findMany({
+            where: {
+                coverImage: null
+            }
+        });
+
+        console.log(`Found ${songs.length} songs without cover image.`);
+
+        for (const song of songs) {
+            try {
+                const filePath = path.join(process.cwd(), 'public/uploads', song.filename);
+                console.log(`Processing ${song.title} (${song.filename})...`);
+
+                const buffer = await readFile(filePath);
+                const metadata = await parseBuffer(buffer);
+                const picture = metadata.common.picture?.[0];
+
+                if (picture) {
+                    const extension = picture.format.split('/')[1] || 'jpg';
+                    const coverFilename = `cover-${Date.now()}-${Math.floor(Math.random() * 1000)}.${extension}`;
+                    const coverPath = path.join(process.cwd(), 'public/uploads/covers', coverFilename);
+
+                    // Ensure directory exists
+                    await writeFile(coverPath, picture.data);
+
+                    // Update DB
+                    await prisma.song.update({
+                        where: { id: song.id },
+                        data: { coverImage: coverFilename }
+                    });
+
+                    console.log(`✅ Extracted cover for ${song.title}`);
+                } else {
+                    console.log(`⚠️ No cover found for ${song.title}`);
+                }
+            } catch (e) {
+                console.error(`❌ Failed to process ${song.title}:`, e.message);
+            }
+        }
+
+        console.log('Migration completed.');
+    } catch (e) {
+        console.error('Migration failed:', e);
+    } finally {
+        await prisma.$disconnect();
+    }
+}
+
+migrate();