Support eqty-pdfgen release packaging

[captjt]

Summary

Adds public-deployment release packaging support for eqty-pdfgen.

• Updates release-platform-package.yaml so manifests declaring charts.eqtyPdfgen also validate the images.eqtyPdfgen entry.
• Publishes/packages the standalone eqty-pdfgen chart before the governance-platform umbrella chart when the release manifest includes it.
• Enables eqty-pdfgen during Helm validation for release manifests that include the chart, including customer registry override rendering.
• Updates Helm CI to render and validate the PDFGen-enabled umbrella path once the chart is synced into this repo.
• Documents eqtyPdfgen in the public release manifest reference and schema.

Sync Behavior

The internal infrastructure repository already syncs charts/** and releases/** into this repo during sync-to-deployment.yaml release mode. Once the infrastructure release branch contains the eqty-pdfgen chart and a manifest with charts.eqtyPdfgen, this workflow will publish/include the PDFGen chart in the public customer package.

This intentionally does not add vc-status-server; the public packaging setup is limited to the current platform services plus eqty-pdfgen.

Validation

• Parsed edited workflow YAML with yq
• Parsed schemas/release-manifest.schema.json with jq
• git diff --check
• Verified existing releases/v0.2.0/release-manifest.yaml still resolves to the original image/chart set
• Verified a temporary manifest containing charts.eqtyPdfgen resolves to eqtyPdfgen and eqty-pdfgen
• Rendered current public governance-platform chart default, Keycloak/external-Postgres, and registry override paths

Known existing gap:

• Full chart lint still reports the existing auth-service metadata issue: chart metadata is missing these dependencies: postgresql.