feat: achieve 370/370 SDLC+Org coverage at 3+ paired runs

Promoted 51 staging runs to official (2329 valid scored tasks across 410 runs).

Changes:
- Clean and promote 14 READY SDLC gap-fill runs (debug/design/document/feature/
  fix/refactor/secure/understand)
- Clean and promote 25 Org runs after extracting clean tasks from Daytona memory-
  exhaustion failures (moved errored task dirs to archive, re-validated, promoted)
- Clean and promote 10 BLOCKED SDLC runs (feature/refactor/secure/test/understand)
  by archiving errored task dirs from DaytonaError: Total memory limit exceeded
- Fix generate_coverage_gap_configs.py: add bare legacy SDLC prefixes (feature_,
  refactor_, etc.) to scan_runs prefix list so bustub-hyperloglog-impl-001 runs
  under feature_haiku_* directories are counted
- Fix prebuild_images.sh: add csb_sdlc_*/csb_org_* to case statement
- Regenerate script registry and index

Coverage: 370/370 canonical tasks at 3+ paired runs (150 SDLC + 220 Org)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sjarmak