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

vi/INDEX.md

@@ -223,7 +223,7 @@ Các script tự động hóa dựa trên sự kiện thực thi tự động.
 **Hook Events** (33, trong 4 nhóm) — khi nào hook chạy:
 - Tool Hooks: PreToolUse, PostToolUse, PostToolUseFailure, PostToolBatch, PermissionRequest, PermissionDenied
 - Session Hooks: SessionStart, Setup, SessionEnd, Stop, StopFailure, SubagentStart, SubagentStop
-- Task Hooks: UserPromptSubmit, UserPromptExpansion, MessageDisplay, TaskCompleted, TaskCreated, TeammateIdle (TaskCompleted/TaskCreated chỉ phát ra khi bật todo tools — tắt mặc định trên Opus 4.8, Sonnet 5, Fable 5, Mythos 5 và mới hơn; `CLAUDE_CODE_ENABLE_TODO_TOOLS=1` khôi phục)
+- Task Hooks: UserPromptSubmit, UserPromptExpansion, MessageDisplay, TaskCompleted, TaskCreated, TeammateIdle (TaskCompleted/TaskCreated chỉ phát ra khi bật todo tools — mặc định chỉ có trên Claude 3.x, Opus 4 đến 4.7, Sonnet 4 đến 4.6 và Haiku 4.5; `CLAUDE_CODE_ENABLE_TODO_TOOLS=1` khôi phục)
 - Lifecycle Hooks: ConfigChange, CwdChanged, DirectoryAdded, FileChanged, PreCompact, PostCompact, PreModelSwitch, PostModelSwitch, WorktreeCreate, WorktreeRemove, Notification, InstructionsLoaded, Elicitation, ElicitationResult
 
 ---
@@ -876,12 +876,13 @@ Muốn thêm ví dụ nữa? Theo cấu trúc:
 
 ---
 
-**Cập Nhật Lần Cuối**: Ngày 15 tháng 8 năm 2026
-**Phiên Bản Claude Code**: 2.1.233
+**Cập Nhật Lần Cuối**: Ngày 19 tháng 9 năm 2026
+**Phiên Bản Claude Code**: 2.1.278
 **Tổng Số Ví Dụ**: 100+ files
 **Danh Mục**: 10 tính năng
 **Hooks**: 8 scripts tự động hóa
 **Ví Dụ Cấu Hình**: 10+ scenarios
 **Sẵn Sàng Sử Dụng**: Tất cả ví dụ
 **Nguồn**:
+- https://code.claude.com/docs/en/tools-reference#task-tool-availability
 - https://code.claude.com/docs/en/hooks