[Refactor]: Migrate repository and artifacts from `llm-d-incubation` to `llm-d` org

[vishbhat]

Problem Statement

The project currently lives under https://github.com/llm-d-incubation/batch-gateway and is wired to that org everywhere in the tree: the Go module path (github.com/llm-d-incubation/batch-gateway), GitHub URLs (README badges, issue templates, docs, examples), and OCI references (ghcr.io/llm-d-incubation/... for container images and oci://ghcr.io/llm-d-incubation/charts for Helm).
Moving the canonical home to https://github.com/llm-d/batch-gateway without updating the repo will break imports for downstream Go consumers, CI/release pushes to the wrong GHCR namespace, default Helm values and install docs pointing at old images/charts, and links to issues and releases.

Proposed Solution

1. Rename / transfer the GitHub repository to llm-d/batch-gateway (or create llm-d/batch-gateway and make it the primary remote), following org policies for transfers, branch protection, and secrets.
2. Single mechanical update in this repo: replace llm-d-incubation with llm-d consistently for:
   • go.mod and test/e2e/go.mod module paths
   • all Go import paths
   • Makefile, docker-bake.hcl, scripts/dev-deploy.sh, scripts/publish-helm-chart.sh
   • .github/workflows (e.g. release REGISTRY and any echoed image names)
   • charts/batch-gateway(values.yaml, Chart.yaml, README)
   • docs, examples, issue templates, release template, and comments that reference GitHub issues or tarball URLs
3. Run go mod tidy at the repo root and under test/e2e/, then run the usual CI (make ci or equivalent) to confirm builds and tests.
4. GitHub / registry setup (outside this repo but part of the issue):
   • Ensure GitHub Actions has permission to push packages to ghcr.io/llm-d/... for the new org (or use org-level GITHUB_TOKEN / PAT as required).
   • Publish charts to oci://ghcr.io/llm-d/charts (or the agreed org chart namespace).
   • Optionally document a transition period (e.g. mirror or deprecate old ghcr.io/llm-d-incubation/* images) if consumers still pull old tags.
5. Close the loop: update any external docs or downstream repos that still reference llm-d-incubation/batch-gateway or old GHCR paths.

Alternatives Considered

No response

Willingness to Contribute

Yes, I can submit a PR

Additional Context

No response