Add unit tests for scripts in kgateway.dev/scripts

[mundele2004]

Summary

Currently, the Python scripts under kgateway.dev/scripts/ do not have unit test coverage (except test-missing-types.py, which currently appears to be broken).

Problem

• Scripts are executed and verified manually
• No automated test coverage exists for:
  • Docs generation scripts
  • Link checking / validation scripts
• Any change to these scripts can introduce regressions without being detected by CI

Why this matters

These scripts play an important role in documentation generation and validation.
Without automated tests:

• Refactoring is risky
• CI cannot catch regressions early
• Contributors must rely on manual verification

Proposed improvement

• Add unit tests for Python scripts under kgateway.dev/scripts/
• Use pytest (or existing preferred framework)
• Mock filesystem and external calls where applicable
• Fix or replace the existing test-missing-types.py

Scope (suggested)

• Cover core logic of scripts (input → output behavior)
• Ensure tests can run as part of CI

Expected outcome

• Safer refactors
• Improved CI reliability
• Better contributor confidence when modifying scripts

I’d be happy to work on this if the maintainers agree with the approach.