Feature/voice authentication

[tayyaba-code]

Fixed the voice enrollment workflow by adding validation, retries, and proper saving of valid recordings.
Improved audio preprocessing (loading, mono conversion, resampling, padding) to make it compatible with the SpeechBrain ECAPA model.
Fixed the embedding extraction pipeline and improved error handling for debugging.
Fixed the model training pipeline so embeddings are generated correctly and used to train the authentication model.
Fixed the voice verification and live authentication flow by removing bugs in waveform handling and authentication logic.
Updated the authentication adapter to use the correct verification method.
Updated and fixed the unit tests to match the implementation changes.
Performed end-to-end testing of the complete pipeline (enrollment → training → authentication).

[Khubaib8281]

Acknowledge Improvements :
yes the audio preprocessing is significantly improved,

• retry logic
• audio validation rather than blindly accepting ,
• unit testing is much improved
• better exception handling
• embedding extraction is reasonably improved and consistent than before

issues need to be addressed:

• this PR is too long, but it'd be much better, if PRs were like, PR1: audio preprocessing, PR2: enrollment improvements. please consider splitting future work into smaller, focused PRs.
• dummy_model.pkl is uploaded, however .pkl is in .gitignore
• coverage.xml file isn't uploaded in artifacts, check the upload coverage job
• still in some files exception isn't used but return False
• consider replacing the remaining print statements with logging

Once these issues are addressed, I'm happy to review the updated changes.

[Khubaib8281]

good about the changes:

• improvement in logging and error handling
• unnecessary files are removed

concern:

• coverage report shows there is no testing for the
  enroll_and_authenticate.py module and embeddings.py | 21% , audio_utils.py | 38%
  , cli.py | 63.33% , verifier.py | 48% , trainer.py | 59% test coverage. overall test coverage is 62% which is moderate but improve the test coverage.

for this PR approval, improve the test coverage

[Khubaib8281]

yes this PR now addresses all the issues mentioned previously and test coverage is substantially improved to 98.58% that's solid.

You can now move to the next feature