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>

README.md

@@ -1,10 +1,10 @@
-# Claude Code Marketplace
+# Claude Code Marketplace - v2.2.0
 
 A collection of Claude Code plugins for project management, infrastructure automation, and development workflows.
 
 ## Plugins
 
-### [projman](./plugins/projman/README.md) v2.2.0
+### [projman](./plugins/projman/README.md)
 **Sprint Planning and Project Management**
 
 AI-guided sprint planning with full Gitea integration. Transforms a proven 15-sprint workflow into a distributable plugin.
@@ -212,7 +212,7 @@ support-claude-mktplace/
     └── validate-marketplace.sh    # Marketplace compliance validation
 ```
 
-## Key Features (v2.2.0)
+## Key Features
 
 ### Parallel Execution
 Tasks are batched by dependency graph for optimal parallel execution: