[Task] Implement Foundational CI/CD Infrastructure

[brightyorcerf]

Problem statement

MUIOGO currently lacks a technical CI gate, meaning every Pull Request requires manual inspection for syntax errors, style violations, and basic logic regressions.

Proposed solution

InIntroduce a foundational GitHub Actions CI workflow that:

• Triggers on all push and pull_request events to main.
• Runs a linting suite using flake8 to enforce PEP 8 standards.
• Establishes a pytest runner environment across a Python 3.10–3.11 matrix.

Acceptance criteria

• CI workflow triggers automatically on GitHub.
• flake8 successfully scans the API/ directory and reports violations.
• pytest runner initializes correctly (exit code 0 for empty test suite).

Dependencies and constraints

None, this is a standalone infrastructure improvement.

Related work checked

helps #301 stability track scope review

Proposed track

None