feat(ci): fast execution caching when unchanged & pre-commit file change tracking integration

[dan-petty]

Context & Rationale

Introduce high-performance execution caching for devops ci quality gates, eliminating redundant 3-minute execution latency when the repository has not changed since the last passing run. Seamlessly integrate with pre-commit file change tracking (pass_filenames: true) and git index/working tree change detection to enable instantaneous pre-commit checks and pre-push verification.

Scope & Deliverables

• Implement dedicated CI caching engine in src/devops_cli/ci/cache.py tracking Git HEAD, working tree/staged diffs, dependency configs (uv.lock, pyproject.toml), and individual file hashes.
• Integrate cache lookup and update into devops ci with --no-cache / --force overrides.
• Update .pre-commit-config.yaml to pass_filenames: true for instant pre-commit validation.
• Maintain cyclomatic complexity \le 10$ and nesting depth $\le 5$.
• 100% pass across all 10 CI quality gates (uv run devops ci).