new structure for transcription engine

- found problems with mps
- integrated jinja2 templates for rendering (.tex?)
- raw ui & bad structure

utils/exceptions.py

@@ -0,0 +1,13 @@
+# not sure, but why not?
+
+class AudioPreparationError(Exception):
+    """Base exception for audio preparation"""
+    pass
+
+class ResamplingError(AudioPreparationError):
+    """Raises when resampling fails"""
+    pass
+
+class DownmixingError(AudioPreparationError):
+    """Raises when downmixing to mono fails"""
+    pass