Audio songs: one-folder storage, version-aware download/share, GPU-checked renders

Storage structure
- All audio tracks (primary + per-language) now live in one folder per song with
  unique lowercase names ({slug}-{lang}-{id}); no more tracks/ subfolder.
- Generated renders (download video + HLS) moved into the song's local-only cache/
  subfolder, separated from source files (never synced to NAS, safe to wipe).
- tracks:reorganize artisan command (dry-run default) consolidates legacy files,
  updates DB paths, and deletes orphans + empty folders.
- CLAUDE.md documents the canonical layout as a global rule (identical local + NAS).

Version-aware download & share
- Download MP3/Video and Share now act on the version being played; ?track={id}
  is carried through share links and auto-selects audio + title + flag + about +
  OG/meta on open.

GPU + visualizer
- Setting::gpuUsable() runs a cached health probe (nvidia-smi + nvenc smoke test,
  256x144) before sending any encode to the GPU; falls back to CPU otherwise.
- Visualizer "Download Video" bakes in equal-width, cover-coloured, translucent
  frequency bars; loop-filter rebuild makes generation ~25x faster.

Image cropper
- result-callback mode + per-song cover-slide cropper in upload/edit (modal + mobile).

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

app/Console/Commands/NasFreeLocalStorage.php

@@ -224,24 +224,27 @@ class NasFreeLocalStorage extends Command
 
         $this->line('  Done scanning banners.');
 
-        // ── Slideshow cache directories ───────────────────────────────────────
-        // The slideshow/ directory is a render cache that is always regenerated on
-        // demand, so its contents are safe to delete unconditionally.
+        // ── Generated/derived renders inside song folders ─────────────────────
+        // Everything under a song's cache/ subfolder (download videos + HLS) is a
+        // render that regenerates on demand, so it is always safe to delete to free
+        // space. Sources (audio, tracks, slides) live outside cache/ and are untouched.
         $this->newLine();
-        $this->info('Scanning slideshow cache…');
+        $this->info('Scanning generated renders (song cache/ folders)…');
 
-        $slideshowDir = storage_path('app/public/slideshow');
-        if (is_dir($slideshowDir)) {
+        $usersRoot = storage_path('app/users');
+        if (is_dir($usersRoot)) {
             $iterator = new \RecursiveIteratorIterator(
-                new \RecursiveDirectoryIterator($slideshowDir, \FilesystemIterator::SKIP_DOTS)
+                new \RecursiveDirectoryIterator($usersRoot, \FilesystemIterator::SKIP_DOTS)
             );
             foreach ($iterator as $file) {
                 if (! $file->isFile()) continue;
+                $path = $file->getPathname();
+                if (! str_contains($path, '/cache/')) continue;
                 $bytes       = $file->getSize();
                 $totalBytes += $bytes;
-                $toDelete[]  = ['label' => 'slideshow', 'path' => $file->getPathname(), 'bytes' => $bytes];
+                $toDelete[]  = ['label' => str_contains($path, '/cache/hls/') ? 'hls' : 'download-video', 'path' => $path, 'bytes' => $bytes];
             }
-            $this->line('  Done scanning slideshow cache.');
+            $this->line('  Done scanning generated renders.');
         }
 
         // ── NAS stream cache (nas_cache/videos/) ──────────────────────────────