Session-end sync trigger

[jordanpartridge]

Problem

When a session ends, insights from that session stay local until the next cron sync or manual sync.

Solution

Add a SessionEnd hook that fires know sync immediately. Ensures cross-machine context is available as fast as possible.

Acceptance Criteria

• SessionEnd hook calls know sync
• Verify entry created in session on Mac is retrievable on Odin within seconds of session end
• No noticeable delay on session close

Part of v1.1.0 release.