CI: add pre-commit config

[himanshu231204]

Background

Development.md references a .pre-commit-config.yaml that doesn't exist.

Why it matters

Local quality gate parity with CI.

Acceptance criteria

• Create .pre-commit-config.yaml (ruff, mypy, bandit).
• Document usage.

Where to look

• Development.md, .pre-commit-config.yaml (new)

How to claim

Comment /claim on this issue.