fix: replace glob() with iterdir() in external_subtitle_files() to handle square brackets in media filenames

Replace glob pattern matching with iterdir() + startswith() filtering to avoid glob interpreting square brackets (e.g., [Bluray-1080p]) as pattern characters. Add OSError exception handling to return empty list when directory access fails.

app.py

@@ -184,7 +184,13 @@ EXTERNAL_SUBTITLE_EXTENSIONS = {".srt", ".ass", ".ssa", ".vtt", ".sub", ".idx",
 
 def external_subtitle_files(path):
     media = Path(path)
-    return sorted(candidate for candidate in media.parent.glob(f"{media.stem}.*") if candidate.suffix.lower() in EXTERNAL_SUBTITLE_EXTENSIONS)
+    prefix = f"{media.stem}."
+    # Nicht glob() verwenden: Mediennamen enthalten oft eckige Klammern
+    # wie [Bluray-1080p], die glob als Pattern-Zeichen interpretieren würde.
+    try:
+        return sorted(candidate for candidate in media.parent.iterdir() if candidate.is_file() and candidate.name.startswith(prefix) and candidate.suffix.lower() in EXTERNAL_SUBTITLE_EXTENSIONS)
+    except OSError:
+        return []
 
 def external_subtitle_languages(path):
     media = Path(path)