Add VBD expansion plan for 1-day demo, 3-day light PoC, and 5-day full PoC

[msfttoler]

Create a planning directory with a comprehensive VBD expansion plan that identifies where to add demos and hands-on lab scenarios for the repository content and GHAS+MDC presentation materials. The plan covers three delivery tiers: 1-Day Executive Demo, 3-Day Light Proof of Concept, and 5-Day Full Proof of Concept.