[jmclong (jmclong)]

Add an external landing page, architecture explanation, source-build guide, and AKS quickstart. Align production, client, controller, and stress-test documentation with the current implementation and public artifact model.

This pull request introduces extensive improvements to the DACS documentation, focusing on clarity, accuracy, and up-to-date guidance for users and contributors. Key additions include a new architecture overview, a streamlined AKS quickstart guide, and an updated build-from-source guide. Several existing docs are revised for correctness and better operational guidance, especially around cache scheduling and scaling.

Major documentation additions:

• Added a comprehensive architecture overview to docs/architecture.md, detailing the control and data planes, system components, request flows, and important boundaries.
• Introduced a new AKS quickstart guide in docs/quickstart.md, providing step-by-step instructions for deploying DACS, running smoke tests, and cleaning up resources.
• Added a detailed build-from-source guide in docs/build-from-source.md, covering prerequisites, build steps, artifact locations, validation, devcontainer usage, and troubleshooting.

Improvements and corrections to existing documentation:

• Updated the DACS Helm chart README to correct the cache enablement flag (cache.enabled), clarify persistent-storage scheduling (now integrated in the controller), and improve troubleshooting instructions. [1] [2]
• Revised the scaling documentation for clarity: references to AKS are generalized to any node pool, and operational guidance points to the main user guide. [1] [2] [3] [4] [5]