fix(helm): restore Dagster 1.1.21 schema validation

[scale-ballen]

Required by scaleapi/Terracode-Infra#8657 and scaleapi/scaleapi#154479.

Dagster 1.1.21 chart schemas reference kubernetesjsonschema.dev. That host now presents a certificate for netlify.app, so Helm 3.12.1 rejects the chart before values are validated or manifests are rendered.

This change:

• replaces only those dead external schema references with the identical Kubernetes 1.18 definitions from instrumenta/kubernetes-json-schema
• pins the schema source to immutable commit 3fb477fb1deb6cc85bbc0cbc2eefc6093f60d6c5
• packages the official Dagster 1.1.21 chart and publishes a branch-local Helm index

Validation:

• the packaged chart differs from the official 1.1.21 chart only in the two values.schema.json files
• helm template succeeds with Helm 3.12.1, matching the Terracode-Infra linter version
• schema validation remains enabled; this does not use a skip-validation flag

Keep draft until the companion migration rollout is ready.

Greptile Summary

This PR restores Dagster 1.1.21 Helm schema loading by replacing the unavailable Kubernetes schema host with commit-pinned GitHub references and publishing a rebuilt chart through a branch-local index.

• Updates external Kubernetes references in the parent and user-deployments schemas.
• Adds the repackaged Dagster 1.1.21 archive and Helm repository index.
• Leaves the schema generator unchanged, causing generated-file validation to fail.

Confidence Score: 4/5

The PR should not merge until the schema generator emits the new pinned references, otherwise the generated-schema CI check fails.

The committed schemas use the replacement host, while the generator still emits the dead host and CI explicitly regenerates the files before requiring a clean diff.

Files Needing Attention: helm/dagster/values.schema.json, helm/dagster/charts/dagster-user-deployments/values.schema.json, helm/dagster/schema/schema/charts/utils/utils.py

Important Files Changed

Filename	Overview
helm/dagster/values.schema.json	Replaces dead external references, but the generated file no longer matches create_definition_ref.
helm/dagster/charts/dagster-user-deployments/values.schema.json	Applies the same reference replacement and has the same generator-drift issue.
helm/dagster/index.yaml	Publishes the rebuilt 1.1.21 chart and existing dependency archives through the branch-local repository.
helm/dagster/release/dagster-1.1.21.tgz	Adds the rebuilt release artifact referenced by the updated index.

Prompt To Fix All With AI

### Issue 1
helm/dagster/values.schema.json:147
**Schema generator restores dead references**

When CI runs `dagster-helm schema apply`, `create_definition_ref` regenerates both schemas with the dead `kubernetesjsonschema.dev` host instead of the newly pinned references, causing `git diff --exit-code` to fail and reintroducing broken Helm validation if the generated output is accepted.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "fix(helm): pin Kubernetes schema source" | Re-trigger Greptile}

Greptile also left 1 inline comment on this PR.

[greptile-apps]

Schema generator restores dead references

When CI runs dagster-helm schema apply, create_definition_ref regenerates both schemas with the dead kubernetesjsonschema.dev host instead of the newly pinned references, causing git diff --exit-code to fail and reintroducing broken Helm validation if the generated output is accepted.

Prompt To Fix With AI

This is a comment left during a code review.
Path: helm/dagster/values.schema.json
Line: 147

Comment:
**Schema generator restores dead references**

When CI runs `dagster-helm schema apply`, `create_definition_ref` regenerates both schemas with the dead `kubernetesjsonschema.dev` host instead of the newly pinned references, causing `git diff --exit-code` to fail and reintroducing broken Helm validation if the generated output is accepted.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.