Fix filtres instruments

frontend/app/page.tsx

@@ -64,8 +64,8 @@ export default function Home() {
     queryKey: ['tracks', filters, page, sortBy, searchQuery],
     queryFn: () => getTracks({
       ...filters,
-      skip: page * limit,
-      limit: searchQuery ? 10000 : limit,  // Load more for search to work across all results
+      skip: searchQuery ? 0 : page * limit,  // Reset skip when searching
+      limit: searchQuery ? 500 : limit,  // Load max 500 for search
       sort_by: sortBy
     }),
   })
@@ -377,7 +377,7 @@ export default function Home() {
                 </div>
 
                 {/* Pagination */}
-                {totalPages > 1 && (
+                {!searchQuery && totalPages > 1 && (
                   <div className="mt-8 flex items-center justify-between">
                     <button
                       onClick={() => setPage(p => Math.max(0, p - 1))}
@@ -402,6 +402,14 @@ export default function Home() {
                     </button>
                   </div>
                 )}
+
+                {/* Search results count */}
+                {searchQuery && (
+                  <div className="mt-4 text-center text-sm text-slate-600">
+                    {filteredTracks.length} résultat{filteredTracks.length > 1 ? 's' : ''} trouvé{filteredTracks.length > 1 ? 's' : ''}
+                    {tracksData && tracksData.tracks.length >= 500 && ' (recherche limitée aux 500 premiers résultats)'}
+                  </div>
+                )}
               </>
             )}
           </div>

frontend/lib/api.ts

@@ -60,7 +60,12 @@ function getApiClient() {
 
 // Tracks
 export async function getTracks(params: FilterParams & { skip?: number; limit?: number }): Promise<TracksResponse> {
-  const response = await getApiClient().get('/api/tracks', { params })
+  const response = await getApiClient().get('/api/tracks', {
+    params,
+    paramsSerializer: {
+      indexes: null, // Use instruments=value1&instruments=value2 instead of instruments[0]=value1
+    }
+  })
   return response.data
 }