webapp: introduce Laravel app under webapp/ for scene overlays

Replaces the per-scene HTML directories (landing/, loading/, game/,
desktop/, goodbye/, music-box/, music/) with a single Laravel app
serving every overlay over HTTP. Supervisord runs `php artisan serve`
on 127.0.0.1:1118 and the OBS scene JSON now references HTTP routes
instead of file:// URLs.

Highlights:
 - public/css/hud.css consolidates the duplicated HUD chrome,
   scanlines/vignette/flicker, terminal styling, and pulse keyframes
   that were copy-pasted across all seven scenes.
 - Blade partials own hud-strip, crt-overlays, obs-ws-scripts,
   camera-frame, screen-frame; the seven scenes extend a shared
   overlay layout.
 - Artisan commands (`rig:setup`, `rig:telemetry`, `rig:loading`,
   `rig:playlist`, `rig:cmd`) replace the shell scripts that wrote
   per-rig JSON snapshots. TwitchHelix + HardwareSnapshot services
   handle the work the bash + Python helpers used to.
 - ObsWsClient + MusicCommandController kill the 250 ms cmd.js poll
   in the music daemon: POST /cmd/{skip|prev|pause|resume} opens a
   short-lived Pawl WS, authenticates, and broadcasts mpd:cmd.
 - AudioController streams files from the configured music dirs so
   CEF can load tracks under the HTTP origin (Chromium blocks
   HTTP-origin pages from loading file:// media).
 - DataController serves /data/playlist.js (with ETag mtime cache)
   and /cover.jpg (no-store) so the existing overlays' window.__PLAYLIST
   and cover.jpg cache-bust pattern keeps working.

scripts/obs-webapp.supervisord.conf is the supervisord unit; install
to /etc/supervisor.d/obs-webapp.conf.
scripts/rewrite-scene-urls.py is a one-shot tool that rewrites
basic/scenes/Default_Stream_HUD.json from file:// to HTTP URLs.
basic/scenes/Default_Stream_HUD.json.pre-webapp is the rollback
artifact (made with OBS closed; full pre-migration state).

The seven old scene directories, vendor/, and the bash scripts are
still on disk pending visual verification; the next commit will
prune them.

webapp/app/Console/Commands/RigPlaylistCommand.php

@@ -0,0 +1,125 @@
+<?php
+
+namespace App\Console\Commands;
+
+use Illuminate\Console\Command;
+use Symfony\Component\Finder\Finder;
+use Symfony\Component\Process\Process;
+use Throwable;
+
+class RigPlaylistCommand extends Command
+{
+    protected $signature = 'rig:playlist';
+    protected $description = 'Index audio under the configured music roots → storage/data/playlist.json';
+
+    private const EXTS = ['m4a', 'mp3', 'opus', 'ogg', 'flac', 'webm', 'aac', 'wav'];
+
+    public function handle(): int
+    {
+        $roots = array_values(array_filter((array) config('rig.music_dirs')));
+        if (empty($roots)) {
+            $this->warn('  ! no music dirs configured (set MUSIC_DIR_1 in .env)');
+        }
+
+        $ffprobe = (string) config('rig.ffprobe', '/usr/bin/ffprobe');
+        if (!is_executable($ffprobe)) {
+            $this->error("  ✗ ffprobe not found at {$ffprobe} (install ffmpeg or set FFPROBE_BIN)");
+            return self::FAILURE;
+        }
+
+        $this->line('── Indexing audio roots ──');
+        foreach ($roots as $r) {
+            $this->line(is_dir($r) ? "    + {$r}" : "    ! {$r} (missing — skipped)");
+        }
+
+        $tracks = [];
+        foreach ($roots as $root) {
+            if (!is_dir($root)) continue;
+            $finder = (new Finder())
+                ->files()
+                ->in($root)
+                ->name('/\.(' . implode('|', self::EXTS) . ')$/i')
+                ->ignoreUnreadableDirs()
+                ->sortByName();
+
+            foreach ($finder as $file) {
+                $name = $file->getFilename();
+                $base = $file->getFilenameWithoutExtension();
+                // Skip yt-dlp intermediates (e.g. foo.f140.m4a, foo.temp.opus).
+                if (preg_match('/\.(?:f\d+|temp|part)$/i', $base)) continue;
+
+                $path = $file->getRealPath();
+                $meta = $this->probe($ffprobe, $path);
+                $tracks[] = [
+                    'title'       => $this->cleanTitle($base),
+                    'file'        => 'file://' . $this->urlEncodePath($path),
+                    'durationSec' => isset($meta['durationSec']) ? (int) $meta['durationSec'] : null,
+                ];
+            }
+        }
+
+        $doc = [
+            'syncedAt'   => gmdate('Y-m-d\TH:i:s\Z'),
+            'sourceDirs' => $roots,
+            'trackCount' => count($tracks),
+            'tracks'     => $tracks,
+        ];
+        $path = rtrim(config('rig.storage_data'), '/') . '/playlist.json';
+        @mkdir(dirname($path), 0775, true);
+        file_put_contents(
+            $path,
+            json_encode($doc, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE)
+        );
+
+        $this->line('');
+        $this->info("  ✓ wrote {$path} ({$doc['trackCount']} tracks)");
+        $this->line('  → refresh the Music Daemon browser source in OBS to reload the queue.');
+        return self::SUCCESS;
+    }
+
+    private function probe(string $ffprobe, string $path): array
+    {
+        try {
+            $proc = new Process([
+                $ffprobe, '-v', 'error',
+                '-show_entries', 'format=duration:format_tags=title,artist',
+                '-of', 'json',
+                $path,
+            ]);
+            $proc->setTimeout(10);
+            $proc->run();
+            if (!$proc->isSuccessful()) return [];
+            $json = json_decode($proc->getOutput(), true) ?: [];
+            $fmt = $json['format'] ?? [];
+            return [
+                'durationSec' => isset($fmt['duration']) ? (float) $fmt['duration'] : null,
+            ];
+        } catch (Throwable) {
+            return [];
+        }
+    }
+
+    /**
+     * Mirrors scripts/playlist.sh's clean_title():
+     *  - drop "| ..." (or fullwidth ｜) tails (genre/label noise)
+     *  - strip trailing YouTube IDs in brackets like "[-XxZTgMWKV0]"
+     *  - strip "[NCS Release]" / "(NCS10 Release)" suffixes
+     */
+    private function cleanTitle(string $t): string
+    {
+        $t = preg_replace('/\s*[｜|].*$/u', '', $t) ?? $t;
+        $t = preg_replace('/\s*\[[A-Za-z0-9_-]{11}\]\s*$/', '', $t) ?? $t;
+        $t = preg_replace(
+            '/\s*[\[(](?:NCS\d*|No Copyright Sounds)(?:\s+Release)?[\])]\s*$/i',
+            '',
+            $t
+        ) ?? $t;
+        return trim($t);
+    }
+
+    private function urlEncodePath(string $path): string
+    {
+        // Same as Python's urllib.parse.quote(..., safe='/') — keep separators, encode the rest.
+        return implode('/', array_map('rawurlencode', explode('/', $path)));
+    }
+}