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.

04-subagents/README.md

@@ -124,7 +124,7 @@ to solving problems.
 | `model` | No | Model to use: `sonnet`, `opus`, `haiku`, full model ID, or `inherit`. Defaults to configured subagent model |
 | `permissionMode` | No | `default`, `acceptEdits`, `dontAsk`, `bypassPermissions`, `plan` |
 | `maxTurns` | No | Maximum number of agentic turns the subagent can take |
-| `skills` | No | Comma-separated list of skills to preload. Injects full skill content into the subagent's context at startup |
+| `skills` | No | Comma-separated list of skills to preload. Injects full skill content into the subagent's context at startup. **v2.1.133+:** subagents also discover project, user, and plugin skills via the Skill tool — same catalog as the main session, no longer limited to their own embedded set. |
 | `mcpServers` | No | MCP servers to make available to the subagent |
 | `hooks` | No | Component-scoped hooks (PreToolUse, PostToolUse, Stop) |
 | `memory` | No | Persistent memory directory scope: `user`, `project`, or `local` |
@@ -1217,11 +1217,12 @@ graph TD
 
 ---
 
-**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/sub-agents
 - https://code.claude.com/docs/en/agent-teams
 - https://github.com/anthropics/claude-code/releases/tag/v2.1.117
 - https://github.com/anthropics/claude-code/releases/tag/v2.1.131
+- https://github.com/anthropics/claude-code/releases/tag/v2.1.138
 **Compatible Models**: Claude Sonnet 4.6, Claude Opus 4.7, Claude Haiku 4.5