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

README.md

@@ -12,7 +12,7 @@
 [![GitHub Stars](https://img.shields.io/github/stars/luongnv89/claude-howto?style=flat&color=gold)](https://github.com/luongnv89/claude-howto/stargazers)
 [![GitHub Forks](https://img.shields.io/github/forks/luongnv89/claude-howto?style=flat)](https://github.com/luongnv89/claude-howto/network/members)
 [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
-[![Version](https://img.shields.io/badge/version-2.1.263-brightgreen)](CHANGELOG.md)
+[![Version](https://img.shields.io/badge/version-2.1.278-brightgreen)](CHANGELOG.md)
 [![Claude Code](https://img.shields.io/badge/Claude_Code-2.1+-purple)](https://code.claude.com)
 
 🌐 **Language / Ngôn ngữ / 语言 / Мова:** [English](README.md) | [Tiếng Việt](vi/README.md) | [中文](zh/README.md) | [Українська](uk/README.md) | [日本語](ja/README.md)
@@ -102,7 +102,7 @@ Run `/lesson-quiz [topic]` after each module. The quiz pinpoints what you missed
 
 - **GitHub stars** from developers who use Claude Code daily
 - **Forks** from teams adapting this guide for their own workflows
-- **Actively maintained** — synced with every Claude Code release (latest: v2.1.263, September 2026)
+- **Actively maintained** — synced with every Claude Code release (latest: v2.1.278, September 2026)
 - **Community-driven** — contributions from developers who share their real-world configurations
 
 [![Star History Chart](https://api.star-history.com/svg?repos=luongnv89/claude-howto&type=Date)](https://star-history.com/#luongnv89/claude-howto&Date)
@@ -201,7 +201,7 @@ cp -r 03-skills/code-review-specialist ~/.claude/skills/
 Yes. MIT licensed, free forever. Use it in personal projects, at work, in your team — no restrictions beyond including the license notice.
 
 **Is this maintained?**
-Actively. The guide is synced with every Claude Code release. Current version: v2.1.263 (September 2026), compatible with Claude Code 2.1+.
+Actively. The guide is synced with every Claude Code release. Current version: v2.1.278 (September 2026), compatible with Claude Code 2.1+.
 
 **How is this different from the official docs?**
 The official docs are a feature reference. This guide is a tutorial with diagrams, production-ready templates, and a progressive learning path. They complement each other — start here to learn, reference the docs when you need specifics.
@@ -487,7 +487,7 @@ Configure hooks in `~/.claude/settings.json`:
 **Hook Events** (33, in 4 categories) — when it runs:
 - **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` and `TaskCreated` only fire when the todo tools are enabled, which is off by default on Opus 4.8, Sonnet 5, Fable 5, Mythos 5, and newer models (`CLAUDE_CODE_ENABLE_TODO_TOOLS=1` restores them)
+- **Task Hooks**: `UserPromptSubmit`, `UserPromptExpansion`, `MessageDisplay`, `TaskCompleted`, `TaskCreated`, `TeammateIdle` — `TaskCompleted` and `TaskCreated` only fire when the todo tools are enabled, which is available by default only on Claude 3.x models, Opus 4 through 4.7, Sonnet 4 through 4.6, and Haiku 4.5 (`CLAUDE_CODE_ENABLE_TODO_TOOLS=1` restores them)
 - **Lifecycle Hooks**: `ConfigChange`, `CwdChanged`, `DirectoryAdded`, `FileChanged`, `PreCompact`, `PostCompact`, `PreModelSwitch`, `PostModelSwitch`, `WorktreeCreate`, `WorktreeRemove`, `Notification`, `InstructionsLoaded`, `Elicitation`, `ElicitationResult`
 
 </details>
@@ -873,9 +873,10 @@ MIT License - see [LICENSE](LICENSE). Free to use, modify, and distribute. The o
 
 ---
 
-**Last Updated**: September 6, 2026
-**Claude Code Version**: 2.1.263
+**Last Updated**: September 19, 2026
+**Claude Code Version**: 2.1.278
 **Sources**:
+- https://code.claude.com/docs/en/tools-reference#task-tool-availability
 - https://code.claude.com/docs/en/hooks
 - https://code.claude.com/docs/en/overview
 - https://code.claude.com/docs/en/changelog