Follow up PR #265: refine chapters, diagrams, and add S20 (#283)

* feat: s01-s14 docs quality overhaul — tool pipeline, single-agent, knowledge & resilience

Rewrite code.py and README (zh/en/ja) for s01-s14, each chapter building
incrementally on the previous. Key fixes across chapters:

- s01-s04: agent loop, tool dispatch, permission pipeline, hooks
- s05-s08: todo write, subagent, skill loading, context compact
- s09-s11: memory system, system prompt assembly, error recovery
- s12-s14: task graph, background tasks, cron scheduler

All chapters CC source-verified. Code inherits fixes forward (PROMPT_SECTIONS,
json.dumps cache, real-state context, can_start dep protection, etc.).

* feat: s15-s19 docs quality overhaul — multi-agent platform: teams, protocols, autonomy, worktree, MCP tools

Rewrite code.py and README (zh/en/ja) for s15-s19, the multi-agent platform
chapters. Each chapter inherits all previous fixes and adds one mechanism:

- s15: agent teams (TeamCreate, teammate threads, shared task list)
- s16: team protocols (plan approval, shutdown handshake, consume_inbox)
- s17: autonomous agents (idle polling, auto-claim, consume_lead_inbox)
- s18: worktree isolation (git worktree, bind_task, cwd switching, safety)
- s19: MCP tools (MCPClient, normalize_mcp_name, assemble_tool_pool, no cache)

All appendix source code references verified against CC source. Config priority
corrected: claude.ai < plugin < user < project < local.

* fix: 5 regressions across s05-s19 — glob safety, todo validation, memory extraction, protocol types, dep crash

- s05-s09: glob results now filter with is_relative_to(WORKDIR) (inherited from s02)
- s06-s08: todo_write validates content/status required fields (inherited from s05)
- s09: extract_memories uses pre-compression snapshot instead of compacted messages
- s16: submit_plan docstring clarifies protocol-only (not code-level gate)
- s17-s19: match_response restores type mismatch validation (from s16)
- s17-s19: claim_task deps list handles missing dep files without crashing

* fix: s12 Todo V2 logic reversal, s14/s15 cron range validation, s18/s19 worktree name validation

- s12 README (zh/en/ja): fix Todo V2 direction — interactive defaults to Task,
  non-interactive/SDK defaults to TodoWrite. Fix env var name to
  CLAUDE_CODE_ENABLE_TASKS (not TODO_V2).
- s14/s15: add _validate_cron_field with per-field range checks (minute 0-59,
  hour 0-23, dom 1-31, month 1-12, dow 0-6), step > 0, range lo <= hi.
  Replace old try/except validation that only caught exceptions.
- s18/s19: add validate_worktree_name() to remove_worktree and keep_worktree,
  not just create_worktree.

* fix: align s16-s19 teaching tool consistency

* fix pr265 chapter diagrams

* Add comprehensive s20 harness chapter

* Fix chapter smoke test regressions

* Clarify README tutorial track transition

---------

Co-authored-by: Haoran <bill-billion@outlook.com>

s08_context_compact/images/compaction-layers.svg

@@ -0,0 +1,98 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 760 590" font-family="system-ui, -apple-system, sans-serif">
+  <defs>
+    <linearGradient id="header" x1="0" y1="0" x2="1" y2="0">
+      <stop offset="0%" stop-color="#1e3a5f"/><stop offset="100%" stop-color="#2563eb"/>
+    </linearGradient>
+    <linearGradient id="pre" x1="0" y1="0" x2="0" y2="1">
+      <stop offset="0%" stop-color="#dbeafe"/><stop offset="100%" stop-color="#bfdbfe"/>
+    </linearGradient>
+    <linearGradient id="auto" x1="0" y1="0" x2="0" y2="1">
+      <stop offset="0%" stop-color="#fecaca"/><stop offset="100%" stop-color="#fca5a5"/>
+    </linearGradient>
+    <linearGradient id="emergency" x1="0" y1="0" x2="0" y2="1">
+      <stop offset="0%" stop-color="#fed7aa"/><stop offset="100%" stop-color="#fdba74"/>
+    </linearGradient>
+    <marker id="arrow-d" viewBox="0 0 10 10" refX="5" refY="10" markerWidth="6" markerHeight="6" orient="auto">
+      <path d="M 0 0 L 5 10 L 10 0 z" fill="#94a3b8"/>
+    </marker>
+  </defs>
+
+  <rect width="760" height="590" fill="#fafbfc" rx="8"/>
+
+  <!-- 标题栏 -->
+  <rect x="0" y="0" width="760" height="44" fill="url(#header)" rx="8"/>
+  <rect x="0" y="36" width="760" height="8" fill="url(#header)"/>
+  <text x="380" y="28" fill="#fff" font-size="15" font-weight="700" text-anchor="middle">上下文压缩 — 预处理管线 + 自动压缩 + 应急兜底</text>
+
+  <!-- 左侧说明 -->
+  <rect x="20" y="62" width="220" height="80" rx="6" fill="#f8fafc" stroke="#cbd5e1" stroke-width="1"/>
+  <text x="130" y="82" fill="#1e3a5f" font-size="12" font-weight="700" text-anchor="middle">设计原则</text>
+  <text x="130" y="100" fill="#475569" font-size="10" text-anchor="middle">便宜的先跑，贵的后跑</text>
+  <text x="130" y="116" fill="#475569" font-size="10" text-anchor="middle">能改文本 → 不删整条</text>
+  <text x="130" y="132" fill="#475569" font-size="10" text-anchor="middle">能删整条 → 不调 LLM</text>
+
+  <!-- 右侧代价箭头 -->
+  <rect x="530" y="62" width="210" height="80" rx="6" fill="#f8fafc" stroke="#cbd5e1" stroke-width="1"/>
+  <text x="635" y="82" fill="#1e3a5f" font-size="12" font-weight="700" text-anchor="middle">代价递增</text>
+  <text x="635" y="104" fill="#475569" font-size="10" text-anchor="middle">文本操作 → LLM 摘要 → 应急裁剪</text>
+  <text x="635" y="124" fill="#94a3b8" font-size="9" text-anchor="middle">0 API · 0 API · 0 API · 1 API · 1 API</text>
+
+  <!-- ===== 预处理管线标题 ===== -->
+  <rect x="20" y="146" width="720" height="24" rx="4" fill="#f1f5f9"/>
+  <text x="55" y="163" fill="#64748b" font-size="11" font-weight="600">预处理管线（执行顺序：L3 → L1 → L2，每轮 LLM 调用前自动执行，0 API）</text>
+
+  <!-- L3: toolResultBudget -->
+  <rect x="80" y="180" width="600" height="46" rx="7" fill="url(#pre)" stroke="#2563eb" stroke-width="1.5"/>
+  <text x="100" y="200" fill="#1e40af" font-size="12" font-weight="600">L3</text>
+  <text x="135" y="200" fill="#1e40af" font-size="13" font-weight="700">toolResultBudget</text>
+  <text x="260" y="200" fill="#1e40af" font-size="11">tool_result 总和 &gt; 200KB → 最大项落盘</text>
+  <text x="650" y="200" fill="#1e40af" font-size="10" text-anchor="end">保留完整内容</text>
+  <text x="135" y="218" fill="#2563eb" font-size="9">触发：每轮自动，必须在 microCompact 之前保留完整内容</text>
+
+  <!-- 箭头 L3→L1 -->
+  <line x1="380" y1="226" x2="380" y2="238" stroke="#94a3b8" stroke-width="1" marker-end="url(#arrow-d)"/>
+
+  <!-- L1: snipCompact -->
+  <rect x="80" y="240" width="600" height="46" rx="7" fill="url(#pre)" stroke="#2563eb" stroke-width="1.5"/>
+  <text x="100" y="260" fill="#1e40af" font-size="12" font-weight="600">L1</text>
+  <text x="135" y="260" fill="#1e40af" font-size="13" font-weight="700">snipCompact</text>
+  <text x="260" y="260" fill="#1e40af" font-size="11">消息 &gt; 50 条 → 裁掉中间</text>
+  <text x="650" y="260" fill="#1e40af" font-size="10" text-anchor="end">保留头尾</text>
+  <text x="135" y="278" fill="#2563eb" font-size="9">触发：消息数超过阈值</text>
+
+  <!-- 箭头 L1→L2 -->
+  <line x1="380" y1="286" x2="380" y2="298" stroke="#94a3b8" stroke-width="1" marker-end="url(#arrow-d)"/>
+
+  <!-- L2: microCompact -->
+  <rect x="80" y="300" width="600" height="46" rx="7" fill="url(#pre)" stroke="#2563eb" stroke-width="1.5"/>
+  <text x="100" y="320" fill="#1e40af" font-size="12" font-weight="600">L2</text>
+  <text x="135" y="320" fill="#1e40af" font-size="13" font-weight="700">microCompact</text>
+  <text x="260" y="320" fill="#1e40af" font-size="11">旧 tool_result → 占位符（保留最近 3 条）</text>
+  <text x="650" y="320" fill="#1e40af" font-size="10" text-anchor="end">压旧结果</text>
+  <text x="135" y="338" fill="#2563eb" font-size="9">触发：每轮自动，教学版用文本占位符模拟</text>
+
+  <!-- ===== 自动压缩标题 ===== -->
+  <rect x="20" y="358" width="720" height="24" rx="4" fill="#f1f5f9"/>
+  <text x="70" y="375" fill="#64748b" font-size="11" font-weight="600">自动压缩决策（预处理不够时触发，1 API 调用）</text>
+
+  <!-- L4: autoCompact -->
+  <rect x="80" y="390" width="600" height="58" rx="7" fill="url(#auto)" stroke="#dc2626" stroke-width="2"/>
+  <text x="100" y="412" fill="#991b1b" font-size="12" font-weight="600">L4</text>
+  <text x="135" y="412" fill="#991b1b" font-size="13" font-weight="700">autoCompact</text>
+  <text x="260" y="412" fill="#991b1b" font-size="11">token 超阈值 → LLM 全量摘要</text>
+  <text x="590" y="412" fill="#991b1b" font-size="10" text-anchor="end">1 API 调用</text>
+  <text x="135" y="428" fill="#dc2626" font-size="9">阈值: contextWindow - maxOutputTokens - 13,000 · 先尝试 sessionMemoryCompact，不够才调 LLM</text>
+  <text x="135" y="442" fill="#dc2626" font-size="9">熔断：连续失败 3 次后停止重试</text>
+
+  <!-- ===== 应急兜底标题 ===== -->
+  <rect x="20" y="460" width="720" height="24" rx="4" fill="#f1f5f9"/>
+  <text x="55" y="477" fill="#64748b" font-size="11" font-weight="600">应急兜底（API 仍然返回 prompt_too_long 时触发）</text>
+
+  <!-- 应急: reactiveCompact -->
+  <rect x="80" y="492" width="600" height="62" rx="7" fill="url(#emergency)" stroke="#c2410c" stroke-width="1.5"/>
+  <text x="100" y="512" fill="#9a3412" font-size="12" font-weight="600">应急</text>
+  <text x="135" y="512" fill="#9a3412" font-size="13" font-weight="700">reactiveCompact</text>
+  <text x="135" y="528" fill="#9a3412" font-size="10">API 返回 413 / prompt_too_long → 字节级裁剪</text>
+  <text x="135" y="544" fill="#c2410c" font-size="9">保留最后 5 条 + 摘要，比 autoCompact 更激进</text>
+
+</svg>