Summary

• Make Pane Chat's generated guide and pane-orchestrator define contract precedence instead of duplicating upstream lifecycle policy.
• Add required raw fallback coverage for Codex/Claude gh-address-comments, PR-test metadata, and Claude review support.
• Fail raw fallback sync when lifecycle-critical required downloads fail, even if stale cached files already exist.
• Update Pane Chat README docs to describe runtime/generated/upstream/downstream responsibility boundaries.

Closes #354

Validation

• pnpm --filter main exec vitest run src/services/skillCacheManager.test.ts
• pnpm --filter main typecheck
• pnpm --filter main lint (passes with existing warnings outside this change)
• git diff --check origin/main..HEAD

Notes

No visual asset is included because this change is limited to generated text, fallback cache coverage, and tests; a diagram would not add useful review evidence.