Add Error Handling for Invalid Date Formats

[swaparup36]

The format_date() function in utils.py doesn't handle invalid date formats. If a user enters a date like "2024-13-45", the program crashes.

File:
utils.py:9

Task:

• Add try-except block to handle ValueError
• Return a helpful error message to the user
• Test with various invalid date formats

Expected Outcome:

# Should handle invalid dates gracefully
format_date("invalid-date")  # Should return error, not crash

[Debjit00]

I am checking this issue.