Rejecting original approach (restricting agents from marking busy). New approach: auto-create AgentSession when new logs arrive from an agent that has no active session. Implementation: In `AgentChannel#flush_terminal_buffer`, when no active session is found for the agent_identifier, auto-create one by: 1. Parsing agent_identifier (e.g., "worker_123") to get agent_type and project_id 2. Finding the matching Agent 3. Creating an AgentSession with status "running" This fixes the root cause - logs have nowhere to go because sessions aren't always explicitly created before logging starts.