chore(studio): mount Regression Health certification artifact

[man4ish]

Summary

• Mounts the promoted Regression Health JSON artifact as a single read-only file.
• Configures the Control Center artifact path and 168-hour freshness threshold.
• Applies to development and release Compose variants.

Validation

• Dev Compose validation: PASS.
• Release Compose validation: PASS.
• Compatibility release Compose validation: PASS.
• Artifact mount is read-only.
• No secrets or unrelated service changes are included in the commit.

Scope

• Deployment wiring only; no certification execution or CI promotion automation.