feat(agents): enhance agent core with state management

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

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

backend/app/agents/schemas/event.py

@@ -7,10 +7,21 @@ from pydantic import BaseModel, Field
 
 
 AgentEventType = Literal[
+    "agent.execution.decided",
+    "agent.parallel.assessed",
+    "agent.skill.shortlisted",
+    "agent.task_graph.built",
+    "agent.subtask.started",
+    "agent.subtask.completed",
+    "agent.merge.completed",
     "agent.tool.start",
     "agent.tool.result",
     "agent.verify.started",
     "agent.verify.completed",
+    "agent.retrospective.created",
+    "agent.learning.decision",
+    "agent.skill.lifecycle.changed",
+    "agent.rollback.triggered",
     "agent.created",
     "agent.spawn.blocked",
     "agent.message.sent",