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/budget.py

@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+from app.agents.schemas.task import CollaborationBudget
+
+
+def build_subtask_budget(
+    *,
+    execution_mode: str,
+    max_parallel_tasks: int,
+    max_tool_calls: int = 2,
+    max_iterations: int = 2,
+    metadata: dict | None = None,
+) -> CollaborationBudget:
+    return CollaborationBudget(
+        mode="collaboration" if execution_mode != "direct" else "direct",
+        max_parallel_tasks=max_parallel_tasks,
+        remaining_parallel_tasks=max_parallel_tasks,
+        max_tool_calls=max_tool_calls,
+        remaining_tool_calls=max_tool_calls,
+        max_iterations=max_iterations,
+        remaining_iterations=max_iterations,
+        escalation_threshold=1,
+        metadata=metadata or {},
+    )