course: Add supplementary module for kagenti ADK + MemoryHub integration

[rdwj]

Context

The MemoryHub MemoryStore protocol landed in kagenti/adk as PR kagenti/adk#231. Kagenti agents can now get governed, cross-session memory by adding kagenti-adk[memoryhub] and wiring the A2A extension. This is a natural addition to the course as a supplementary module.

What the module should cover

1. Deploy kagenti to the cluster -- install the kagenti ADK server alongside the existing calculus agent stack
2. Deploy MemoryHub -- stand up the MemoryHub service (or point at an existing instance)
3. Wire MemoryStore into an agent -- use the MemoryHubExtensionSpec / MemoryHubExtensionServer pattern from the SDK docs to give an agent durable memory
4. Exercise it -- demonstrate search, create, and curation rejection in a running agent
5. Client-side fulfillment -- show how a calling client supplies MemoryHubFulfillment metadata (API key path and OAuth path)

Placement

This should be a supplementary module (not inserted into the core 00-11 track). Something like supplementary/kagenti-memoryhub.md or a new numbered module after the current track. The existing course stands alone without it.

References

• feat: Add MemoryStore protocol for cross-session agent memory kagenti/adk#231 (merged PR with protocol, implementation, tests, docs, and example agent)
• kagenti/adk docs/development/sdk/memory.mdx for the SDK reference
• kagenti/adk examples/agent-integration/memoryhub/memoryhub-recall/ for the working example
• https://github.com/redhat-ai-americas/memory-hub for MemoryHub itself