[Core] Rename module path to sigs.k8s.io/ome

[pallasathena92]

What this PR does

Renames the Go module path from github.com/sgl-project/ome to sigs.k8s.io/ome, a stable vanity import path following the kubernetes-sigs convention. GitHub-hosted references (release URLs, sigstore certificate identity, helm repo URL, issue templates, docs) are updated to github.com/ome-projects/ome to reflect the new GitHub org.

Changes touch:

• 4 go.mod files (root + hack/internal/tools, site, web-console/backend)
• All Go imports across cmd/, pkg/, internal/, tests/
• Generated code: zz_generated.deepcopy.go, pkg/openapi/openapi_generated.go, pkg/openapi/swagger.json, all of pkg/client/{clientset,informers,listers}
• Linker flags in Makefile and 4 Dockerfiles (pkg/version ldflags)
• Codegen scripts: hack/update-codegen.sh, hack/update-openapigen.sh, hack/genref/config.yaml, violation exception lists
• CI workflows: .github/workflows/release.yaml, openvex.yaml
• PROJECT metadata, README, CONTRIBUTING, Hugo site config, web-console frontend

Intentionally not touched: SGLang upstream link, ghcr.io/sgl-project/genai-bench benchmark image references, OME container registry path (registry migration is a separate decision).

Why we need it

The repo was moved from github.com/sgl-project/ome to github.com/ome-projects/ome, so the Go module declaration and all import paths needed updating. Rather than pin imports to the new GitHub org name, we adopt the kubernetes-sigs vanity path sigs.k8s.io/ome — the same convention used by other Kubernetes ecosystem projects (sigs.k8s.io/controller-runtime, sigs.k8s.io/gateway-api, etc.). This decouples Go imports from where the repo lives on GitHub, so future moves don't require another mass-rename across the codebase.

The K8s API group (ome.io) and PROJECT repo: metadata reflect that this is a Kubernetes-native operator naturally suited to the kubernetes-sigs convention.

Caveat — external resolution requires follow-up: go get sigs.k8s.io/ome will return 404 from external consumers until (a) the repo moves to github.com/kubernetes-sigs/ome via Kubernetes SIG adoption, and (b) a PR to kubernetes/k8s.io adds the vanity mapping. These are tracked as separate workstreams. In the interim, the module is internally consistent and consumable via a replace directive.

Fixes #

How to test

Verify the rename is internally consistent

# All packages compile in all 4 modules
go build ./...
(cd hack/internal/tools && go build ./...)
(cd web-console/backend && go build ./...)

# No stragglers (must be empty)
git grep "github.com/sgl-project/ome"

# Remaining sgl-project references are only the intentional ones (SGLang, genai-bench)
git grep "sgl-project" | grep -vE "sglang|genai-bench"

# Tests pass (pkg/xet has one pre-existing failure unrelated to this PR)
make test


<!-- Steps to verify, or "N/A" for docs/config changes -->

## Checklist

- [ ] Tests added/updated (if applicable)
- [ ] Docs updated (if applicable)
- [ ] `make test` passes locally