Fix: Handle empty/whitespace inputs in process_questions and add ligh…

[GitAd7]

Summary:
This PR fixes a critical bug in Harmony’s matching pipeline where empty or whitespace-only inputs (e.g., "" vs "") were incorrectly producing a similarity score of 1.0.

Changes:

1. Updated process_questions to explicitly set TextVector.vector = None when input text is empty or whitespace.
2. Added unit-level tests to verify that empty/whitespace strings result in None vectors.
3. Extended higher-level tests to ensure downstream similarity results correctly return None instead of misleading scores.
4. Introduced mocking of add_text_to_vec across tests to avoid loading the pretrained model, making the test suite CI-friendly and faster to run.

Impact:

1. Prevents false-positive matches in similarity scoring.
2. Improves correctness when handling edge cases (empty/whitespace input).
3. Significantly reduces test execution time by removing model downloads.

[jaydugad]

All tests are passing locally on Python 3.11, including the ones that were failing before. Going to merge this now.
Thanks @GitAd7.

[GitAd7]

Hi @jaydugad, I'm very pleased to know that all the test cases are passing locally, this being my first open-source contribution means a lot to me. I would also like to contribute to more issues and solve them, also would love to connect with you on linkedin. Thanks

[jaydugad]

That’s awesome to hear! On my GitHub account, I have added my LinkedIn profile - let's connect.