[Feature] Add Bank of Baroda statement parser

[rohitthink]

Problem

Bank of Baroda is one of India's largest public sector banks but FreeFile doesn't support parsing their statements yet.

Proposed Solution

Create a new parser at backend/parsers/bob.py that can handle Bank of Baroda PDF and CSV statements.

How to contribute

1. Look at existing parsers in backend/parsers/ (e.g., hdfc.py, sbi.py) for the pattern
2. Your parser should return a list of transaction dicts with: date, description, amount, type ("credit"/"debit"), balance
3. Register the parser in the upload route
4. Add test cases with a sample statement

See CONTRIBUTING.md for the full guide.