Implement Automated Session Summarization Workflow

To improve context and continuity between sessions, the agent's startup protocol needs to be enhanced. When a new session starts with the memory core enabled, the agent should automatically summarize the work of the previous session.

This creates a virtuous cycle where the end of one session's work becomes the starting context for the next.

Acceptance Criteria

1. The .github/AGENTS.md file is updated to include a new step in the "Session Initialization" sequence.
2. This new step instructs the agent to, if the memory core is active, find the sessionId of the most recent previous session.
3. If a previous session ID is found, the agent must execute npm run ai:summarize-session on that ID.
4. This step should be positioned after the memory core check in the initialization process.