Extract shared integration-job infra provisioning into a composite action (DRY amber-integration + platform-integration)

[mengw15]

Task Summary

#6274 added a platform-integration job that provisions postgres + MinIO + LakeFS, alongside amber-integration's postgres + MinIO + Lakekeeper. The two jobs now duplicate a lot of infra-provisioning shell (Start Postgres / Create Databases / Start MinIO / Start LakeFS+Lakekeeper), which will drift as image versions, ports, or setup steps change.

Factor the common provisioning into a reusable composite action (.github/actions/setup-texera-infra/action.yml) that both jobs uses:, parameterized by which services to bring up (postgres / minio / lakefs / lakekeeper) and by OS — one source of truth.

Current state

• amber-integration: inlines Start Postgres / Create Databases / Start MinIO / Start Lakekeeper + warehouse-init, with per-OS (docker / brew) branches.
• platform-integration (ci: add platform-integration job to boot each service against real infra #6274): inlines postgres (services container) / Create Databases / Start MinIO / Start LakeFS, ubuntu-only.
• The object-store + schema bring-up logic is duplicated across the two.

Suggested direction

• Add .github/actions/setup-texera-infra (composite), handling the docker / brew OS branching internally.
• Inputs to toggle each service (postgres / minio / lakefs / lakekeeper) and pass OS.
• Refactor both amber-integration and platform-integration to call it, so infra bumps / fixes land in one place.

Follow-up to #6274; related to #6047 (which generalizes the sbt-side @IntegrationTest mechanism — this is the CI-infra counterpart).

Task Type

• Refactor / Cleanup
• DevOps / Deployment / CI
• Testing / QA
• Documentation
• Performance
• Other

[github-actions]

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