Cache dependency security scans and record timeouts

[bsbodden]

Summary

• Add dependency-file scan caching keyed by path and modification time
• Add configurable per-file scan timeout handling
• Record scan timeout/errors separately from vulnerability counts

Closes #6

Tests

• uv run pytest tests/test_dependency_security.py -q
• uv run ruff check src/mfcqi/metrics/dependency_security.py tests/test_dependency_security.py

[github-actions]

✅ MFCQI Score: 0.87 → (±0.000)

➡️ Previous: 0.87

Code quality meets the minimum threshold (0.70).

[github-actions]

✅ MFCQI Score: 0.87 → (±0.000)

➡️ Previous: 0.87

Code quality meets the minimum threshold (0.70).

[github-actions]

✅ Code Quality Report

Metric	Score	Status
MFCQI Score	0.8710134303164616	✅ Good
Test Coverage	82%	✅ Good
Security Issues	0	✅ Clean

Quality Gates

• MFCQI Score: ✅ Minimum 0.75 (Current: 0.8710134303164616)
• Test Coverage: ✅ Minimum 80% (Current: 82%)
• Security: ✅ Zero vulnerabilities (Current: 0)

🎉 All quality gates passed! This PR maintains high code quality standards.

📊 View detailed MFCQI breakdown

Run mfcqi analyze src/mfcqi locally to see detailed metrics breakdown.

[github-actions]

✅ MFCQI Score: 0.87 → (±0.000)

➡️ Previous: 0.87

Code quality meets the minimum threshold (0.70).

[github-actions]

✅ Code Quality Report

Metric	Score	Status
MFCQI Score	0.8712723491166509	✅ Good
Test Coverage	81%	✅ Good
Security Issues	0	✅ Clean

Quality Gates

• MFCQI Score: ✅ Minimum 0.75 (Current: 0.8712723491166509)
• Test Coverage: ✅ Minimum 80% (Current: 81%)
• Security: ✅ Zero vulnerabilities (Current: 0)

🎉 All quality gates passed! This PR maintains high code quality standards.

📊 View detailed MFCQI breakdown

Run mfcqi analyze src/mfcqi locally to see detailed metrics breakdown.