feat(orchestration): add orchestration system with task scheduling

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/app/agents/orchestration/subagent_runtime.py

@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from app.agents.schemas.orchestration import SubTaskSpec
+from app.agents.schemas.task import AgentTask
+
+
+def subtask_spec_to_agent_task(spec: SubTaskSpec) -> AgentTask:
+    return AgentTask(
+        task_id=spec.subtask_id,
+        title=spec.title,
+        owner_agent_id=spec.role,
+        role=spec.role,
+        goal=spec.goal,
+        parent_task_id=spec.parent_run_id,
+        child_task_ids=[],
+        expected_evidence=spec.expected_evidence,
+    )