docs: add / update videos demos

[maximilien]

1. Onboarding, BYOK
2. Create agents and add skills
3. Create teams of agents from templates
4. Monitor, budgets, logging

[maximilien]

Status update: acknowledged. We are prioritizing customer-facing runtime and workflow correctness fixes first, then we will circle back and package short demo videos once the current 1.4.0 behavior is stable.

[maximilien]

Marking this as high priority for upcoming work. Flagging as urgent so we can prioritize recording and publishing the demo videos next.