feat(beaver): 完成Task Team功能v1实现，重构后端架构支持统一内核

新增内部Task系统，包括验证、反馈门控机制，实现自动质量验证
(通过率>=0.75)和用户反馈闭环(satisfied/revise/abandon)。

实现Agent Team v1协调器，支持sequence/parallel/dag执行策略，
sub-agent复用主AgentLoop，每个run使用独立memory snapshot。

建立Skill学习pipeline，包含draft/审核/发布/回滚完整生命周期，
通过Task验证通过且用户满意才生成学习候选。

重构目录结构，移除third_party依赖，建立统一engine内核，
所有agent共享运行时基础组件。

更新ContextBuilder清理provider消息字段，增强SkillContext版本管理，
集成TaskExecutionPlanner和TaskSkillResolver实现技能解析机制。

app-instance/backend/tests/unit/test_process_projection.py

@@ -0,0 +1,122 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from beaver.engine.session import SessionManager
+from beaver.memory.runs import RunMemoryStore, RunRecord
+from beaver.services.process_service import SessionProcessProjector
+
+
+def test_process_projection_maps_task_team_events(tmp_path: Path) -> None:
+    session = SessionManager(tmp_path)
+    run_store = RunMemoryStore(tmp_path / "memory" / "runs")
+    run_store.append_run_record(
+        RunRecord(
+            run_id="sub-run",
+            session_id="sub-session",
+            task_id="task-1",
+            attempt_index=1,
+            task_text="sub task",
+            started_at="2026-01-01T00:00:01+00:00",
+            ended_at="2026-01-01T00:00:02+00:00",
+            success=True,
+            finish_reason="stop",
+        )
+    )
+    run_store.append_run_record(
+        RunRecord(
+            run_id="main-run",
+            session_id="web:test",
+            task_id="task-1",
+            attempt_index=1,
+            task_text="main task",
+            started_at="2026-01-01T00:00:03+00:00",
+            ended_at="2026-01-01T00:00:04+00:00",
+            success=True,
+            finish_reason="stop",
+        )
+    )
+    session.append_message(
+        "web:test",
+        role="system",
+        event_type="task_execution_planned",
+        event_payload={
+            "task_id": "task-1",
+            "attempt_index": 1,
+            "plan_mode": "team",
+            "strategy": "sequence",
+            "node_ids": ["research"],
+            "skill_queries": ["research workflow"],
+            "selected_skill_names": ["research-workflow"],
+            "skill_resolution_report": [
+                {
+                    "node_id": "research",
+                    "skill_query": "research workflow",
+                    "selected_skill_names": ["research-workflow"],
+                    "generated_skill_draft_id": None,
+                    "ephemeral_used": False,
+                    "reason": "matched published skill",
+                }
+            ],
+            "reason": "needs research",
+        },
+        context_visible=False,
+    )
+    session.append_message(
+        "web:test",
+        role="system",
+        event_type="task_team_run_completed",
+        event_payload={
+            "task_id": "task-1",
+            "attempt_index": 1,
+            "team_success": True,
+            "team_run_ids": ["sub-run"],
+            "node_results": [
+                {
+                    "node_id": "research",
+                    "success": True,
+                    "output_text": "evidence",
+                    "run_id": "sub-run",
+                    "skill_query": "research workflow",
+                    "selected_skill_names": ["research-workflow"],
+                    "ephemeral_skill_names": [],
+                    "generated_skill_draft_id": None,
+                    "ephemeral_used": False,
+                    "finish_reason": "stop",
+                }
+            ],
+        },
+        context_visible=False,
+    )
+    session.append_message(
+        "web:test",
+        role="system",
+        event_type="task_synthesis_completed",
+        event_payload={"task_id": "task-1", "attempt_index": 1, "main_run_id": "main-run"},
+        context_visible=False,
+    )
+    session.append_message(
+        "web:test",
+        run_id="main-run",
+        role="system",
+        event_type="task_validation_snapshotted",
+        event_payload={
+            "task_id": "task-1",
+            "attempt_index": 1,
+            "validation_result": {"accepted": True, "score": 0.9},
+            "retry_scheduled": False,
+        },
+        context_visible=False,
+    )
+
+    projection = SessionProcessProjector(session, run_store).project("web:test")
+
+    run_ids = {run["run_id"] for run in projection["runs"]}
+    assert "task:task-1:attempt:1" in run_ids
+    assert "sub-run" in run_ids
+    assert "main-run" in run_ids
+    sub_run = next(run for run in projection["runs"] if run["run_id"] == "sub-run")
+    assert sub_run["metadata"]["selected_skill_names"] == ["research-workflow"]
+    assert sub_run["metadata"]["skill_query"] == "research workflow"
+    assert any(event["actor_name"] == "Validator" for event in projection["events"])
+    assert any(run["session_id"] == "web:test" for run in projection["runs"])