docs: restructure repo — extract tools file, add CLAUDE.md, date-based versioning

- Move ECC setup guide reference from README to claude-code-tools.md
- Add CLAUDE.md with mandatory README sync rule
- Add "Last updated" date to README
- README is now a clean index of repo contents

README.md

@@ -1,40 +1,14 @@
 # Claude Code Facts
 
-A collection of interesting and useful facts, tips, and tools for working with Claude and Claude Code — including plugins, MCP servers, and practical usage patterns.
+> Last updated: 2026-03-23
 
-## MCP Servers
+A collection of interesting and useful facts, tips, tools, and guides for working with Claude and Claude Code.
 
-MCP (Model Context Protocol) servers are external processes that provide tools to Claude Code via a standardized protocol. They run alongside your session and extend Claude's capabilities.
+## Contents
 
-### Context7
+### [Claude Code Tools & Extensions](claude-code-tools.md)
 
-Up-to-date documentation and code examples for any library, available directly in your Claude Code session.
-
-- **Website:** <https://context7.com/>
-- **Setup:**
-
-  ```bash
-  claude mcp add --scope user --transport http context7 https://mcp.context7.com/mcp --header "CONTEXT7_API_KEY: <YOUR_API_KEY>"
-  ```
-
-- **Note:** API key can be created for free after signing in at [context7.com](https://context7.com/)
-
-## Skills (Slash Commands)
-
-Skills are a different extension mechanism from MCPs. They are prompt-based extensions invoked via `/skill-name` commands directly within Claude Code — no external server required.
-
-### AST Index
-
-Fast code search skill for Claude Code — find classes, symbols, usages, implementations, and more across large codebases using AST parsing.
-
-- **Repository:** <https://github.com/defendend/Claude-ast-index-search>
-- **Usage:** Invoke with `/ast-index` or related commands like "find class", "search for symbol", etc.
-
-## Guides
-
-### [Everything Claude Code (ECC) — Setup Guide](ecc-setup-guide.md)
-
-Step-by-step instructions for setting up [Everything Claude Code](https://github.com/affaan-m/everything-claude-code) on a new machine — a comprehensive collection of skills, rules, agents, and hooks for Claude Code.
+MCP servers, skills, and plugins that extend Claude Code — including Context7 (library docs) and AST Index (fast code search).
 
 ### [CI/CD for Python Apps on Gitea](gitea-python-ci-cd.md)