Review MCOL-5781 (columnstore_repair) and revisit scope/plan

Revisit MCOL-5781 "Create columnstore_repair | post dbrm restore or crash" in this sprint, as agreed in the 2026-09-24 comment there.

Inputs to review:

• Allen's product framing (recovery tool to shorten recovery time, not to prevent crashes; long-standing customer ask since MCOL-312)
• Kyle's findings: cpimport blindly trusts the EM post DBRM restore; script for missing-LBID recovery
• Sergey's note: test what MCOL-6338 does on corrupted data; MCOL-6338 currently cannot use data in S3
• Whether it is a blocker for the Amdocs upgrade

Expected outcome: updated scope, breakdown and estimate for MCOL-5781, with a recommendation on next steps.