Improve error message when schema validation fails in validate_questions.py

[tahamuzammil100]

Description

When running utils/validate_questions.py, if a questions/<id>_<slug>/meta.json is missing a required field (per schemas/question.schema.json), the script outputs a stack-trace but the error message is not clearly pointing to the exact file and field causing the failure.

Steps to Reproduce

1. Create a new question folder questions/999_test_problem/ with meta.json missing the difficulty field.
2. Run python utils/validate_questions.py.
3. Observe the script fails with a generic “validation error” stack-trace, but not the specific “meta.json field ‘difficulty’ missing” for folder 999_test_problem.

Expected Behaviour

The error message should clearly indicate:

• the path of the offending folder (e.g., questions/999_test_problem/meta.json)
• the exact missing or invalid field (e.g., difficulty)
• optionally a link or pointer to the schema definition.

Actual Behaviour

Only a generic error is shown in the console/log and one has to dig through the stack-trace to find which question folder caused it.

Environment

• Repository commit: latest main branch as of opening this issue
• Python version: (e.g., 3.11)
• OS: (e.g., macOS/Linux)

Suggestion

Modify validate_questions.py to catch schema validation exceptions and wrap them in a custom error message that includes file path, offending field, and perhaps suggestions for fix.