docs: close 5.8.0 punch list — version sync, stale header, emoji clarity

- Fix /review command visual header: replace inline CLOSING box with
  skill reference (Code Reviewer uses 🔍 REVIEW, not 🏁 CLOSING)
- Update CLAUDE.md version 5.4.0 → 5.8.0, fix data-platform version
  in plugin table (1.1.0 → 1.3.0), update Last Updated date
- Add Unicode emoji to Phase Registry tables in visual-output.md
  (now shows 🎯 Target instead of just "Target")

Items verified complete:
- README.md already shows v5.8.0
- marketplace.json already shows 5.8.0
- CHANGELOG 5.8.0 entry complete (rfc-reject in both Changed/Removed)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/projman/commands/review.md

@@ -44,10 +44,7 @@ See `skills/review-checklist.md` for complete patterns:
 
 ## Visual Output
 
-```
-╔══════════════════════════════════════════════════════════════════╗
-║  📋 PROJMAN                                                      ║
-║  🏁 CLOSING                                                      ║
-║  Code Review                                                     ║
-╚══════════════════════════════════════════════════════════════════╝
-```
+See `skills/visual-output.md`. This command invokes the **Code Reviewer** agent:
+- Phase Emoji: 🔍
+- Phase Name: REVIEW
+- Context: Sprint Name