Improve README and About discoverability

[RayLi-Muye]

Closes #24

Scope

• Rework the README into a clearer first-visit path inspired by the high-level information architecture of aws/aws-cdk: concise product definition, jump links, capabilities, quick start, local development, architecture, repo map, roadmap, contribution workflow, and safety boundary.
• Preserve the repo's public-safe positioning around Kubernetes/EKS GPU render worker orchestration.
• Sync GitHub About metadata with the README positioning.

Acceptance Criteria

• New readers can quickly tell what the repo does, who it is for, what it demonstrates, how to run it locally, and where deeper docs live.
• README does not claim to provision production AWS resources or include private renderer/customer material.
• GitHub description/topics are aligned with the README.

Validation

• PATH=/tmp/codex-renderfarm-tools/bin:$PATH make test
• make smoke-local
• PATH=/tmp/codex-renderfarm-tools/bin:$PATH scripts/render-examples.sh
• git diff --check

GitHub About

Updated description to: Reusable Helm toolkit for GPU-backed render worker orchestration on Kubernetes and EKS.

Added/kept relevant topics including renderfarm, kubernetes, helm, keda, gpu, eks, sqs, helm-chart, infrastructure-as-code, and autoscaling. Removed portfolio-project.

Docs Impact

README only. Existing docs links remain the source for deeper architecture, development, roadmap, and evidence-map detail.

Risk / Rollback

Risk is low because this is documentation and repository metadata only. Rollback is reverting this README commit and, if needed, restoring the previous GitHub About metadata.