Add sound selector to widgets

deploy/php/sounds_list.php

@@ -0,0 +1,41 @@
+<?php
+
+/*
+ * Chat Grid sounds list endpoint.
+ *
+ * Returns a JSON array of filenames found in sounds/widgets/ relative to
+ * the document root. Filters to .ogg, .mp3, and .wav files.
+ * Returns [] if the directory does not exist or contains no audio files.
+ */
+
+header('Content-Type: application/json');
+header('Cache-Control: no-store');
+
+$dir = rtrim($_SERVER['DOCUMENT_ROOT'] ?? '', '/') . '/sounds/widgets';
+
+if (!is_dir($dir)) {
+    echo '[]';
+    exit;
+}
+
+$files = scandir($dir);
+if ($files === false) {
+    echo '[]';
+    exit;
+}
+
+$allowed = ['ogg', 'mp3', 'wav'];
+$results = [];
+
+foreach ($files as $file) {
+    if ($file === '.' || $file === '..') {
+        continue;
+    }
+    $ext = strtolower(pathinfo($file, PATHINFO_EXTENSION));
+    if (in_array($ext, $allowed, true)) {
+        $results[] = $file;
+    }
+}
+
+sort($results);
+echo json_encode($results, JSON_UNESCAPED_SLASHES);