chore: revive project foundations

[techgaun]

Summary

• add unit tests and a Python 3.10-3.13 CI matrix
• produce standards-compliant CSV output and close output files safely
• align package, requirements, and CLI versions
• move CI and Docker from end-of-life Python 3.8 to Python 3.12
• install the package itself in Docker and update the Docker build action
• document local test execution and ignore generated artifacts

Why this is separate from dictionary updates

This PR establishes a tested, current foundation first. New and reorganized dork dictionaries can follow in focused PRs with easier review and lower regression risk.

Verification

• python3 -m unittest discover -s tests -v
• git diff --check
• docker build -t github-dorks:revival .
• docker run --rm github-dorks:revival -v → github-dork.py 0.1.1