[P1] Add CI For Python, Frontend, Docker Build, And Security Checks

[barvhaim]

Roadmap Item 10: Add CI For Python, Frontend, Docker Build, And Security Checks

Priority: P1
Area: DevOps
References: .pre-commit-config.yaml, pyproject.toml, frontend/package.json,
Dockerfile

The repo has commands for linting, formatting, tests, and frontend build, but no visible
CI workflow in the current tree.

Scope:

• Add GitHub Actions for Python tests, Black check, Pylint, frontend lint/build, and
  Docker build.
• Cache uv and npm dependencies.
• Run with no external API credentials by default.
• Optionally add dependency vulnerability scanning.

Acceptance criteria:

• Pull requests get status checks for backend tests, frontend build, and Docker build.
• CI does not require real OpenAI, VirusTotal, WatsonX, or Chrome Stats credentials.
• Failing lint/test/build commands are actionable from logs.

---

Created from docs/roadmap.md.