docs: sync to Claude Code v2.1.278 (#183)

* docs: sync to Claude Code v2.1.278

Type: docs

Audit of the tutorial against Claude Code 2.1.278 (repo baseline was
2.1.263). Fixes claims the repo asserts that are now false; new-feature
coverage is English-only.

P0 - the repo stated the opposite of current behavior:
- AGENTS.md: the claude-md skill said Claude Code "does not read
  AGENTS.md directly" in all 5 languages. It has since v2.1.277, when no
  CLAUDE.md exists at or above the working directory.
- /output-style: listed as "Removed in v2.1.91" in 5 languages and in
  09-advanced-features. Re-added in v2.1.269; row moved out of the
  Deprecated Commands table.
- Permission rules: setup-auto-mode-permissions.py seeded Write(*),
  Glob(*) and NotebookEdit(*), which Claude Code accepts but never
  consults and warns about at startup. Removed; same fix in the
  config-examples.json profile and the 06/09 category tables.
- taskOutputMaxChars: documented as live. The TaskOutput tool was
  removed in v2.1.278 and the key is inert.

P1:
- Dynamic workflow "medium" guideline is fewer than 10 agents, not 15;
  the default is small on Pro plans since v2.1.271.
- Todo-tool availability restated as the official allowlist (Claude 3.x,
  Opus 4-4.7, Sonnet 4-4.6, Haiku 4.5) instead of a denylist; 23 sites
  across 5 languages.
- Memory hierarchy now notes the AGENTS.md fallback.
- Auto-mode classifier cost qualified: not charged on Enterprise plans
  and Claude API accounts since v2.1.278.

P3 (English only): full AGENTS.md section in 02-memory; omitClaudeMd
subagent field; plugin eval / --json / --accept-command / --marketplace;
maxEffortLevel, bashEditDiffEnabled, syncClaudeAi*, 4 env vars,
--system-prompt-snapshot, --plugin-dir folders; send-now key and Monitor
deadlines; checkpoints subagent-edit limitation.

Learning skills audited clean: 100 quiz questions and 100 Review
pointers all valid, 20 self-assessment options correctly mapped.

Cross-file anchors: 15 broken before, 15 after, 0 introduced.

* docs: address review — stale version stamps, /output-style re-add, permission tables

ja/INDEX.md

@@ -229,7 +229,7 @@ blog-draft/
 **フックイベント**（33 件、4 カテゴリ）— 実行タイミング：
 - ツール系フック：PreToolUse、PostToolUse、PostToolUseFailure、PostToolBatch、PermissionRequest、PermissionDenied
 - セッション系フック：SessionStart、Setup、SessionEnd、Stop、StopFailure、SubagentStart、SubagentStop
-- タスク系フック：UserPromptSubmit、UserPromptExpansion、MessageDisplay、TaskCompleted、TaskCreated、TeammateIdle（TaskCompleted と TaskCreated は todo ツールが有効なときのみ発火 — Opus 4.8、Sonnet 5、Fable 5、Mythos 5 以降ではデフォルト無効。`CLAUDE_CODE_ENABLE_TODO_TOOLS=1` で復活）
+- タスク系フック：UserPromptSubmit、UserPromptExpansion、MessageDisplay、TaskCompleted、TaskCreated、TeammateIdle（TaskCompleted と TaskCreated は todo ツールが有効なときのみ発火 — Claude 3.x、Opus 4〜4.7、Sonnet 4〜4.6、Haiku 4.5 でのみデフォルト有効。`CLAUDE_CODE_ENABLE_TODO_TOOLS=1` で復活）
 - ライフサイクル系フック：ConfigChange、CwdChanged、DirectoryAdded、FileChanged、PreCompact、PostCompact、PreModelSwitch、PostModelSwitch、WorktreeCreate、WorktreeRemove、Notification、InstructionsLoaded、Elicitation、ElicitationResult
 
 ---
@@ -882,8 +882,8 @@ Run tests in background
 
 ---
 
-**最終更新**：2026 年 8 月 15 日
-**Claude Code バージョン**：2.1.233
+**最終更新**：2026 年 9 月 19 日
+**Claude Code バージョン**：2.1.278
 **互換モデル**：Claude Sonnet 4.6、Claude Opus 4.7、Claude Haiku 4.5
 **例題総数**：100 ファイル超
 **カテゴリ**：10 機能
@@ -891,6 +891,7 @@ Run tests in background
 **設定例**：10 シナリオ以上
 **すぐ使える**：すべての例
 **情報源**：
+- https://code.claude.com/docs/en/tools-reference#task-tool-availability
 - https://code.claude.com/docs/en/overview
 - https://code.claude.com/docs/en/hooks
 - https://code.claude.com/docs/en/commands