Enhance audio verification features and improve code structure

- Added `ffmpeg` as a dependency in `flake.nix` and `package-cleanup.nix` for audio file property analysis.
- Updated `main.py` to include new functions for retrieving audio file properties using `ffprobe` and verifying audio matches with detailed confidence scoring.
- Refactored fingerprint comparison logic to improve accuracy and added logging for better traceability.
- Enhanced the `find_duplicate_singles` function to support audio verification results and confidence scores, providing clearer output for users.

nix/package-cleanup.nix

@@ -12,9 +12,17 @@ pkgs.python3Packages.buildPythonApplication {
     requests
     python-dotenv
   ];
+  
+  # Runtime dependencies for audio verification
   buildInputs = [
     pkgs.chromaprint
+    pkgs.ffmpeg
   ];
+  
+  makeWrapperArgs = [
+    "--prefix PATH : ${pkgs.lib.makeBinPath [ pkgs.ffmpeg pkgs.chromaprint ]}"
+  ];
+  
   meta = {
     mainProgram = "lidarr-cleanup-singles";
     description = "Identify duplicate single tracks in Lidarr";