ci: implement automated quality gating

[brightyorcerf]

Linked issue

• Closes [Task] Implement Foundational CI/CD Infrastructure #375
• Related Stability track scope review for the current local-use model #301

Existing related work reviewed

Issues/PRs reviewed: > checked pr-intake.yml and sync-project-priority-from-labels.yml. Confirmed these are strictly governance and project management workflows:

• pr-intake.yml only validates PR structure/templates via scripts/check_pr_intake.py.
• sync-project.yml manages project board priorities via labels.

No workflow currently exists to gate on Python technical quality, PEP 8 compliance, or logic regressions. This PR fills that specific infrastructure gap.

Overlap assessment

• Classification: New Infrastructure
• Overlapping items: PR ci(security): add Bandit static analysis workflow. #365 (Security/Bandit)
• Why this is not duplicate/superseded: PR ci(security): add Bandit static analysis workflow. #365 focuses strictly on Security (SAST). This PR (ci: implement automated quality gating #376) establishes the Code Quality and Testing baseline (Flake8/Pytest). Together, these PRs provide a comprehensive CI/CD suite for the Stability Track. This PR specifically gates on the 2,800+ linting issues which Bandit does not cover.

Why this PR should proceed

This PR establishes a baseline for code quality that is currently missing. By automating flake8 and pytest, we ensure that future contributions adhere to PEP 8 standards and do not introduce syntax regressions.

Summary

• What changed: Added .github/workflows/ci_quality.yml
• Why: To provide immediate feedback on code quality for all incoming PRs. A local audit identified 2,881 baseline style violations that this CI will now track and help remediate.

Tooling versions (flake8, pytest) are pinned to ensure consistent linting results across all contributor environments, preventing 'ghost' failures from upstream tool updates

Validation

• Tests added/updated: Established the pytest runner contract.
• Validation steps documented: Verified the workflow triggers flake8 correctly in a local environment.
• Evidence attached screenshot

Documentation

• Setup/workflow changes reflected: PR status checks will now show a "Code Quality" pass/fail mark.

Scope check

• No unrelated refactors
• Implemented from a feature branch
• Change is deliverable without upstream OSeMOSYS/MUIO dependency
• Base repo/branch is EAPD-DRB/MUIOGO:main (not upstream)

Exception rationale

blank

[brightyorcerf]

Note: the current 'Red' status on the Code Quality checks is expected.

It is successfully flagging the baseline linting violations. This establishes the necessary 'Health Dashboard' required for the codebase.