feat: 3.2.17中途变更处理(git驱动) + 3.2.9a Worker git强制 + 3.2.5 Phase7 squash merge + Arc git初始化检测

- 新增 ChangeClassifier（爆炸半径分类：IMPLEMENTATION/INTERFACE/GLOBAL_CONSTRAINT）
- 新增 ImpactPropagator（BFS影响传播：IMPACTED/BOUNDARY/SAFE差异化标记）
- task_graph.py：invalidate_by_adr()差异化失效 + CascadeReport扩展字段（向后兼容）
- eng_mode.py：三阶段差异化流程（分类→传播→失效→git操作→验证任务→重规划）
- eng_mode.py：_git_squash_merge_and_tag() + Phase 7 集成
- do_mode.py：_ensure_all_committed() Worker git操作强制
- adr_watcher.py：内容快照 + get_content_for_classification()
- events.py：ADR_CLASSIFIED/IMPACT_PROPAGATED/BOUNDARY_VERIFICATION_GENERATED
- partial_replanner.py：replan_with_constraints() + generate_verification_tasks()
- project_bootstrap.py：ensure_git_initialized() Arc规划前检测
- test_p1_21_phase2.py：21个新测试，95个全量测试0失败

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/air_runtime/partial_replanner.py

@@ -73,6 +73,62 @@ class PartialReplanner:
 
         return delta
 
+    def replan_with_constraints(self, graph: TaskGraph,
+                                 invalidated_ids: list[str],
+                                 frozen_interfaces: list[Interface],
+                                 new_adr_path: Path | None = None) -> PlanDelta:
+        """带冻结接口约束的局部重规划（3.2.17 Phase 3）。
+
+        frozen_interfaces 来自 SAFE 已完成任务，重规划不能破坏这些接口。
+        """
+        delta = PlanDelta()
+
+        affected_context = self._collect_affected_context(graph, invalidated_ids)
+        stable_interfaces = self._extract_stable_interfaces(graph, set(invalidated_ids))
+
+        all_frozen = list(stable_interfaces)
+        for fi in frozen_interfaces:
+            if not any(s.task_id == fi.task_id for s in all_frozen):
+                all_frozen.append(fi)
+
+        replan_request = {
+            "type": "partial-replan",
+            "invalidatedTaskIds": invalidated_ids,
+            "affectedContext": [ctx.__dict__ for ctx in affected_context],
+            "stableInterfaces": [iface.__dict__ for iface in all_frozen],
+            "newAdrPath": str(new_adr_path) if new_adr_path else None,
+        }
+        delta.replan_request = replan_request
+        return delta
+
+    def generate_verification_tasks(self, graph: TaskGraph,
+                                     boundary_task_ids: list[str]) -> PlanDelta:
+        """为 BOUNDARY 已完成任务生成验证任务（3.2.17 Phase 3.4）。
+
+        验证任务检查 BOUNDARY 任务的兼容性，确认是否与新 ADR 一致。
+        """
+        from air_runtime.task_graph import TaskNode, Edge
+        delta = PlanDelta()
+        for idx, tid in enumerate(boundary_task_ids):
+            node = graph.nodes.get(tid)
+            if not node or node.status != "DONE":
+                continue
+            verify_id = f"{tid}-VFY"
+            verify_node = TaskNode(
+                id=verify_id,
+                status="TODO",
+                task=f"[边界验证] 验证 {tid} ({node.task}) 与新 ADR 的兼容性",
+                files_dirs=node.files_dirs,
+                done_when="兼容性确认通过",
+                write_set=list(node.write_set),
+                test_required=True,
+            )
+            delta.added_tasks.append(verify_node)
+            delta.edge_changes.added.append(Edge(
+                source=tid, target=verify_id, kind="verification",
+            ))
+        return delta
+
     def _collect_affected_context(self, graph: TaskGraph,
                                    invalidated_ids: list[str]) -> list[ReplanContext]:
         """收集受影响任务的上下文。"""