feat(driver-versions): improve workflow with idempotency, retry logic, and caching

[castrojo]

Summary

• Enhanced driver versions workflow with idempotency guarantees to prevent duplicate PRs
• Added retry logic with exponential backoff for resilience against network failures
• Implemented NVIDIA driver URL caching (committed to git) for performance
• Comprehensive documentation in AGENTS.md covering architecture, troubleshooting, and maintenance
• Updated monthly reports formatting to Hyperlight-style single-line changelog format

Key Improvements

Idempotency

• Script checks if release already exists before adding
• Deduplicates all rows by tag name within each section
• Only writes file if content changes
• Workflow checks for existing open PR before creating new one
• Uses static branch name to prevent duplicate branches

Resilience

• 3 retries with exponential backoff (2s, 4s, 8s delays)
• Applies to GitHub API calls and NVIDIA website fetching
• Rate limit detection with graceful exit
• Handles transient network failures automatically

Performance

• NVIDIA cache committed to git reduces scraping by ~80%
• Cache persists across workflow runs
• Only fetches URLs for new drivers (cache miss)

Documentation

• Complete workflow architecture and data flow
• Troubleshooting guide with common issues
• Schedule and manual triggering instructions
• NVIDIA cache persistence rationale
• Upstream dependencies reference

Changes

• .github/workflows/update-driver-versions.yml - Idempotency checks and PR handling
• scripts/update-driver-versions.js - Retry logic, caching, deduplication
• .nvidia-drivers-cache.json - Committed driver URL cache
• AGENTS.md - Comprehensive workflow documentation
• scripts/lib/markdown-generator.mjs - Hyperlight-style formatting
• reports/*.mdx - Regenerated with new formatting

Testing

• ✅ Tested locally with GITHUB_TOKEN
• ✅ Verified idempotency (multiple runs produce no changes)
• ✅ Validated cache persistence
• ✅ Built and served site successfully
• ✅ Regenerated December 2025 and January 2026 reports