Regenerate snapshot/xray.db from a fresh example run

[LukasPoque]

The committed inspector demo snapshot is stale:

• Old migration baseline — openStore can't migrate it ("table conversations already exists").
• Predates recording_started_at, so spans now render Untimed instead of attributed to turns.

Fix: re-run the example agent on the current SDK (sends X-Recording-Started-At), let the analyze chain finish, checkpoint the WAL, and commit the new snapshot/xray.db at the current schema head.