feat: add Album model, artist/search/upload controllers, requireArtist middleware

src/controllers/searchController.js

@@ -0,0 +1,42 @@
+import Track from '../models/Track.js';
+
+export const searchController = {
+  async search(req, res, next) {
+    try {
+      const query = (req.query.q || '').trim();
+
+      if (!query) {
+        return res.json({
+          success: true,
+          data: { tracks: [], artists: [], albums: [] },
+        });
+      }
+
+      const regex = new RegExp(query.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'), 'i');
+
+      const tracks = await Track.find({
+        $or: [
+          { title: regex },
+          { artist: regex },
+          { album: regex },
+        ],
+      })
+        .select('-__v')
+        .sort({ createdAt: -1 })
+        .limit(50)
+        .lean();
+
+      const artistNames = [...new Set(tracks.map(t => t.artist))];
+      const artists = artistNames.map(name => ({ name }));
+
+      const albumNames = [...new Set(tracks.map(t => t.album))];
+      const albums = albumNames.map(name => ({ name }));
+
+      const data = { tracks, artists, albums };
+
+      return res.json({ success: true, data });
+    } catch (error) {
+      return next(error);
+    }
+  },
+};