fix: P1-21 code-to-design 审计修复 — pending 分组 + apply_full_replace

- invalidate_by_adr 新增 pending 分组：ADR 直接关联的 TODO 任务也标记 INVALIDATED
- apply_full_replace 保留 DISPATCHED 状态，不再保留 INVALIDATED（全量替换时重置）
- 新增 2 项测试：apply_full_replace 状态保留 + 真实 git revert
- 测试从 11→13 项，全部通过

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

lib/air_runtime/task_graph.py

@@ -89,8 +89,10 @@ class TaskGraph:
             self._add_edge(edge)
 
     def apply_full_replace(self, nodes: list[TaskNode], edges: list[Edge]) -> None:
-        """全量替换模式：Arc 产出完整 DAG，保留已完成任务状态。"""
-        done_status = {tid: n.status for tid, n in self.nodes.items() if n.status == "DONE"}
+        """全量替换模式：Arc 产出完整 DAG，保留已完成任务状态。
+        INVALIDATED 状态不保留（已被级联失效标记的任务在全量替换时重置）。"""
+        done_status = {tid: n.status for tid, n in self.nodes.items()
+                       if n.status in ("DONE", "DISPATCHED")}
         self.nodes = {n.id: n for n in nodes}
         self.edges = list(edges)
         for tid, status in done_status.items():
@@ -267,6 +269,7 @@ class TaskGraph:
         affected = self.tasks_by_adr(adr_id)
         completed = [t for t in affected if t.status == "DONE"]
         in_progress = [t for t in affected if t.status == "DISPATCHED"]
+        pending = [t for t in affected if t.status == "TODO"]
 
         # 1. 冻结调度
         self.dispatch_frozen = True
@@ -281,8 +284,13 @@ class TaskGraph:
             t.status = "INVALIDATED"
             delta.removed_tasks.append(t.id)
 
-        # 4. 级联失效下游
-        downstream_ids = self._find_downstream([t.id for t in completed + in_progress])
+        # 4. 标记 ADR 直接关联的 TODO 任务为 INVALIDATED
+        for t in pending:
+            t.status = "INVALIDATED"
+            delta.removed_tasks.append(t.id)
+
+        # 5. 级联失效下游
+        downstream_ids = self._find_downstream([t.id for t in completed + in_progress + pending])
         cascaded = []
         for tid in downstream_ids:
             node = self.nodes.get(tid)
@@ -291,8 +299,8 @@ class TaskGraph:
                 delta.removed_tasks.append(tid)
                 cascaded.append(tid)
 
-        # 5. 回滚快照引用（由调用方在 git revert 后填入）
-        all_invalidated = [t.id for t in completed + in_progress] + cascaded
+        # 6. 回滚快照引用（由调用方在 git revert 后填入）
+        all_invalidated = [t.id for t in completed + in_progress + pending] + cascaded
 
         return CascadeReport(
             invalidated_completed=len(completed),