Guard missing rename mode output - #7345

Summary

• treat a missing mode output from the rename scan like the existing missing-delta path
• avoid dereferencing the optional output when the scan produces no matching entry

Validation

• configured and built the full project with six parallel jobs, including the test targets
• the local test partition passes
• focused analysis is clean at 1/1 translation units and the independently reproduced path is gone
• eight of twelve test partitions pass locally; the remaining remote transport partitions require their external endpoint setup