fix: consolidate version display to main README.md only

Version standardization:
- Move version to main README.md title: "Claude Code Marketplace - v2.2.0"
- Remove version from plugins/projman/README.md title
- Remove version from plugins/projman/CONFIGURATION.md title
- Remove version from plugin listings in README.md
- Remove "Key Features (v2.2.0)" -> "Key Features"
- Remove Version section from plugins/projman/README.md
- Remove version references from CLAUDE.md structure comments

Added versioning rule to CLAUDE.md:
- Version displayed ONLY in main README.md title
- Do NOT add versions to plugin docs or config guides
- Version history maintained in CHANGELOG.md only

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

plugins/projman/CONFIGURATION.md

@@ -1,4 +1,4 @@
-# Configuration Guide - Projman Plugin v2.0.0
+# Configuration Guide - Projman Plugin
 
 Complete setup and configuration instructions for the Projman project management plugin.