Post-Compaction Feedback Survey

What: After memory compaction events, users can optionally provide feedback on the compaction quality.

Details:

• Survey message: "How did that compaction go? (optional)" at line 481872
• Analytics event: tengu_post_compact_survey_event at line 477154
• Survey appears after compaction operations complete
• Auto-hides after 3 seconds (oj3 = 3000 at line 477153)
• Implemented via V39() hook at line 477101
• Evidence: Feature completely absent in v2.0.58