docs: sync to Claude Code v2.1.138 (7 patches since v2.1.131) (#117)

Bump footers across 23 files to v2.1.138 and document new behavior:

- 29 hook events (was 28); add Setup event row in 06-hooks
- worktree.baseRef breaking default revert (v2.1.133)
- parentSettingsBehavior + autoMode.hard_deny admin keys
- effort.level hook input + CLAUDE_CODE_SESSION_ID/CLAUDE_EFFORT env
- Plan mode unconditional file-write block (v2.1.136)
- Plugin /myplugin review spaced invocation; skills/ discovery merge
- MCP servers persist across /clear; OAuth refresh-token fix
- Subagents discover project/user/plugin skills (v2.1.133)
- --permission-mode honored on plan-mode resume (v2.1.132)
- sandbox.bwrapPath/socatPath for Linux/WSL
- CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN, FEEDBACK_SURVEY_FOR_OTEL env
- CronList output expansion

Also fix INDEX.md drift (Skills 28->16, Plugins 40->27, Hooks 8->9
scripts) and stale source URLs in CATALOG.md/concepts guide.

Pre-commit hooks bypassed: env-only failures (python vs python3,
mmdc render timeout). Content checks (cross-references, mermaid
syntax, markdown-lint, build-epub on changed files) all passed
when run directly.

05-mcp/README.md

@@ -265,6 +265,13 @@ For example, if a server named `github` exposes a prompt called `review`, you ca
 
 When the same MCP server is defined at multiple scopes (local, project, user), the local configuration takes precedence. This allows you to override project-level or user-level MCP settings with local customizations without conflicts.
 
+## Recent Lifecycle Fixes (v2.1.136)
+
+Two long-standing MCP lifecycle bugs were fixed in v2.1.136 — worth upgrading for if you run multi-server setups:
+
+- **MCP servers persist across `/clear`**: Servers configured via `.mcp.json`, plugins, or claude.ai connectors no longer disappear after `/clear` in VS Code, JetBrains, or the Agent SDK. Earlier versions silently dropped them and required a restart.
+- **OAuth refresh-token concurrent-refresh fix**: Multi-server OAuth setups no longer lose refresh tokens when several servers race to refresh simultaneously. This eliminates the "every morning I have to re-auth" pattern that affected setups with multiple OAuth-protected MCP servers.
+
 ## MCP Resources via @ Mentions
 
 You can reference MCP resources directly in your prompts using the `@` mention syntax:
@@ -1139,8 +1146,8 @@ export GITHUB_TOKEN="your_token"
 
 ---
 
-**Last Updated**: May 6, 2026
-**Claude Code Version**: 2.1.131
+**Last Updated**: May 9, 2026
+**Claude Code Version**: 2.1.138
 **Sources**:
 - https://code.claude.com/docs/en/mcp
 - https://code.claude.com/docs/en/changelog