Add GitHub Actions analysis with performance and correctness findings

[Copilot]

Comprehensive analysis of all workflow files identifying performance bottlenecks, coverage gaps, and correctness issues.

Key Findings

Performance Issues:

• Coverage job runs ~65min on every PR (candidates for scheduled/non-blocking)
• 9-job build matrix (3 Rust versions × 3 OS) on every push
• No timeouts configured - hung jobs can consume resources indefinitely
• Estimated 1-2hr potential savings per PR

Correctness Issues:

• YAML anchors use non-standard syntax (&rust_stable in env section, lines 18-20)
• MSRV set to 1.88 (non-existent Rust version)
• Inconsistent caching strategy across jobs

Coverage Gaps:

• No cargo doc verification with -D warnings
• Examples not built/tested in CI matrix
• Security audit runs post-merge, not during PR review
• Benchmarking limited to single package despite multi-package workspace

Analysis Structure

The document (GITHUB_ACTIONS_ANALYSIS.md) provides:

• Detailed workflow-by-workflow analysis
• Prioritized recommendations (high/medium/low)
• Estimated impact and specific implementation guidance
• Best practices assessment

Recommended Actions

Immediate: Fix YAML anchors, add timeouts, verify MSRV
Short-term: Optimize PR matrix, make coverage non-blocking, add doc verification
Long-term: Expand benchmarking coverage, test examples, refine caching

No workflow changes made per requirements - analysis only.

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