Add research note: VMware Tanzu Platform AI

[rkoster]

What is this note about?

How VMware Tanzu Platform (Broadcom's commercial distribution built around Cloud Foundry)
is adapting to AI workloads on two tracks: the "GenAI on Tanzu Platform" tile (LLM hosting
as an ordinary OSBAPI broker/tile) and "Tanzu Platform agent foundations" (a proprietary
secure-by-default agentic runtime on VMware Cloud Foundation with buildpack-built agent
containers, structural secrets isolation, zero-trust sandboxing, and a centralized AI
gateway).

Checklist

• My note lives in research/ and uses a lowercase kebab-case filename.
• It starts from research/TEMPLATE.md and has valid frontmatter
  (title, author, date, tags, status, sources).
• It has the four sections: Summary, Key findings, CF relevance, Open questions.
• I added relevant tags (see the suggested vocabulary in IDEATION.md).
• Sources are linked.
• It's on-topic for agentic workloads on Cloud Foundry