Improve pull request review readability and fresh-checkout delivery

[forhappy]

Summary

• Prepare a fresh GitHub Action checkout with an explicit local --code-only history profile before running compass review.
• Resolve retained semantic entity identities to human-readable names in PR finding statements, verification reasons, reviewer actions, and SARIF messages.
• Preserve stable source/target entity identities and finding fingerprints for machine traceability.
• Add regression coverage and update the PR review documentation and compatibility notes.

Why

Fresh Action checkouts previously failed when non-code files required semantic extraction without credentials. Human-facing PR findings also exposed opaque sha256: entity IDs even though Compass already had display-name evidence.

Validation

• 12 compass-pr-intelligence report-contract tests
• 3 compass-output PR review tests
• 7 CLI review tests
• 2 compass-core PR review tests
• Clippy for compass-pr-intelligence
• Rust formatting, product-boundary validation, and diff checks
• 11 GitHub Action delivery tests
• Real CLI11 PR #1213 qualification completed with LocalExact evidence; text, Markdown, JSON, SARIF, and readiness outputs succeeded