fix: Windows兼容性修复 + P1-24弱模型优化 + 3.2.9b禁止降级方案 + AirRvr三层审查放行标准

- lock.py: 跨平台进程锁（Unix fcntl / Windows msvcrt / O_CREAT|O_EXCL降级）
- eng_mode.py/eng_orchestrator.py: hasattr(os, "getloadavg") Windows防护
- arc_mode.py: 路径分隔符 replace("\\", "/") Windows兼容
- deploy_runtime.py: 修复语法错误（清理 import tempfile 残留）
- P1-24(3.2.18): AMBIGUOUS_VERBS歧义词检测 + SAFE_VERBS安全动词 + validate_task_description()
- TaskNode.keep_constraints 保留约束字段 + JSON序列化
- _build_graph_from_todo 返回歧义警告 + Arc自检集成
- 3.2.9b: FORBIDDEN_DEGRADATION_PATTERNS + check_forbidden_degradation()
- AirRvr三层审查放行标准: ReviewVerdict + evaluate_review_pass() + is_forbidden_pass_reason()
- commands/arc.md: 弱模型安全重写（操作类型拆分+保留约束+自检）
- commands/do.md/eng.md/rvr.md: 禁止降级方案 + 三层审查标准
- 测试: 7个新测试 + 74全量通过

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/air_runtime/modes/arc_mode.py

@@ -107,19 +107,22 @@ def _export_task_graph_json(graph: TaskGraph, path: Path) -> None:
                         "filesDirs": n.files_dirs, "doneWhen": n.done_when,
                         "inDegree": n.in_degree, "outEdges": n.out_edges,
                         "writeSet": n.write_set, "testRequired": n.test_required,
-                        "adrRefs": n.adr_refs}  # P1-21
+                        "adrRefs": n.adr_refs,  # P1-21
+                        "keepConstraints": n.keep_constraints}  # P1-24
                   for nid, n in graph.nodes.items()},
         "edges": [{"source": e.source, "target": e.target, "kind": e.kind} for e in graph.edges],
     }
     atomic_json_write(path, data)
 
 
-def _build_graph_from_todo(todo_path: Path) -> tuple[TaskGraph, list[str]]:
-    """从 todo.md 构建初始 DAG，返回图和未满足 Done When 条件的任务列表。"""
+def _build_graph_from_todo(todo_path: Path) -> tuple[TaskGraph, list[str], list[str]]:
+    """从 todo.md 构建初始 DAG，返回图、Done When 违规列表、歧义词警告列表。"""
     from air_runtime.todo_parser import parse_tasks
+    from air_runtime.review import validate_task_description
     tasks = parse_tasks(todo_path)
     graph = TaskGraph()
     violations = []  # P1-19.1: 记录 Done When 不含"测试通过"的任务
+    ambiguity_warnings = []  # P1-24: 弱模型优化 — 歧义词警告
 
     for t in tasks:
         # P1-21: 从 todo.md ADR 列提取 adr_refs
@@ -137,10 +140,13 @@ def _build_graph_from_todo(todo_path: Path) -> tuple[TaskGraph, list[str]]:
         if t.done_when and "测试通过" not in t.done_when:
             violations.append(t.task_id)
 
+        # P1-24: 弱模型优化 — 检测歧义词
+        ambiguity_warnings.extend(validate_task_description(t.task_id, t.task))
+
     # P1-19.1: 注入边界测试任务
     _inject_boundary_tests(graph, tasks)
 
-    return graph, violations
+    return graph, violations, ambiguity_warnings
 
 
 def _inject_boundary_tests(graph: TaskGraph, tasks: list) -> None:
@@ -159,8 +165,8 @@ def _inject_boundary_tests(graph: TaskGraph, tasks: list) -> None:
             for fd in t.files_dirs.split(","):
                 fd = fd.strip()
                 if fd:
-                    # 取第一级目录作为模块名
-                    parts = fd.split("/")
+                    # 取第一级目录作为模块名 (跨平台路径解析)
+                    parts = fd.replace("\\", "/").split("/")
                     if len(parts) > 1:
                         module = parts[0]
                     else:
@@ -238,7 +244,7 @@ def parallel_review_mode(project_root: Path, todo_path: Path) -> dict:
     review_md_path.write_text(render_review_markdown(review), encoding="utf-8")
 
     # 构建 DAG（包含边界测试任务注入）
-    graph, done_when_violations = _build_graph_from_todo(todo_path)
+    graph, done_when_violations, ambiguity_warnings = _build_graph_from_todo(todo_path)
     for edge_info in review.to_dict().get("edges", []):
         graph.add_edge(Edge(source=edge_info["source"], target=edge_info["target"],
                            kind=edge_info.get("kind", "dependency")))
@@ -264,6 +270,7 @@ def parallel_review_mode(project_root: Path, todo_path: Path) -> dict:
         "conflicts": [c.to_dict() for c in review.conflicts],
         "serializationPoints": review.serialization_points,
         "doneWhenViolations": done_when_violations,  # P1-19.1: Done When 不含"测试通过"的任务
+        "ambiguityWarnings": ambiguity_warnings,  # P1-24: 弱模型优化 — 歧义词警告
         "boundaryTestTasks": [n.id for n in graph.nodes.values() if n.test_required],
         "safetyWarnings": safety_warnings,  # INV-16: 弱模型安全警告
     }
@@ -292,6 +299,7 @@ def parallel_review_mode(project_root: Path, todo_path: Path) -> dict:
             "parallel_group_count": len(review.parallel_groups),
             "conflict_count": len(review.conflicts),
             "done_when_violations": done_when_violations,
+            "ambiguity_warnings": ambiguity_warnings,
             "boundary_test_task_count": len([n for n in graph.nodes.values() if n.test_required])}
 
 
@@ -301,7 +309,7 @@ def incremental_replan_mode(project_root: Path, todo_path: Path, previous_graph_
     _ensure_dirs(paths)
 
     review = build_parallel_review(todo_path)
-    new_graph, _ = _build_graph_from_todo(todo_path)
+    new_graph, _, _ = _build_graph_from_todo(todo_path)
     for edge_info in review.to_dict().get("edges", []):
         new_graph.add_edge(Edge(source=edge_info["source"], target=edge_info["target"],
                                 kind=edge_info.get("kind", "dependency")))