[CI] Run tests on pull requests, not just master push

[Armaan-Raisinghani]

The current CI workflow (.github/workflows/ci-run-tests.yml) only triggers on pushes to master and workflow_dispatch. This means pull requests are never validated by CI before merging.

Current Behavior:

• Tests only run after code is pushed to master
• PRs can be merged without any automated testing

Expected Behavior:

• Tests should run on every PR targeting master
• Contributors get CI feedback before merge

Additional Notes:
There is also a duplicate "Install Poetry" step — once via pipx install poetry (line 18) and again via pip install poetry (line 27). Only one is needed.