GitHub PR patch completeness

Trap: files_listing_complete=true, patch_selection_truncated=false, and patch_unavailable_count=0 look like proof that implementation patches are present, but changed_files may still exceed—or exist without—the supplied patch sources. Fix: reconcile source components with changed_files; preserve any mismatch as an evidence limitation and verify only what body and metadata independently prove. Missing patches do not automatically require abstention, but never infer their contents or detailed implementation.