docs: update Last Updated date and Claude Code version across all files

Update all documentation footers from generic "April 2026 / 2.1+" to
the specific sync date (April 9, 2026) and documented version (2.3.0).
Also add version/date footers to zh/CATALOG.md and
zh/01-slash-commands/README.md which were missing them.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

02-memory/README.md

@@ -1151,6 +1151,6 @@ For the most up-to-date information, refer to the official Claude Code documenta
 - [Official Memory Docs](https://code.claude.com/docs/en/memory) - Anthropic documentation
 
 ---
-**Last Updated**: April 2026
-**Claude Code Version**: 2.1+
+**Last Updated**: April 9, 2026
+**Claude Code Version**: 2.3.0
 **Compatible Models**: Claude Sonnet 4.6, Claude Opus 4.6, Claude Haiku 4.5

02-memory/directory-api-CLAUDE.md

@@ -61,4 +61,4 @@ Error responses:
 - Tag cache keys with resource type
 
 ---
-**Last Updated**: April 2026
+**Last Updated**: April 9, 2026

02-memory/personal-CLAUDE.md

@@ -60,4 +60,4 @@ project/
 - **Test Framework**: Jest with React Testing Library
 
 ---
-**Last Updated**: April 2026
+**Last Updated**: April 9, 2026

02-memory/project-CLAUDE.md

@@ -88,4 +88,4 @@
 - Admin Panel: `/projects/admin`
 
 ---
-**Last Updated**: April 2026
+**Last Updated**: April 9, 2026