Prepare 0.3.0 alpha 5

[Jason-Doyle]

Summary

• Release the validated Kubernetes, Azure, AWS, and GCP deployment templates.
• Publish the bootstrap-role command, client-side SCRAM role bootstrap, runtime grant reconciliation, and managed PostgreSQL CA/hostname verification.
• Ship the shared deployment contract, Helm chart, Bicep module, OpenTofu modules, provider locks, validation script, and deployment documentation.
• Update package, container, README, environment example, changelog, and benchmark evidence to 0.3.0-alpha.5.

Validation

• 42 release and PostgreSQL tests
• Package runtime and type smoke tests
• Helm tag/digest, TLS, proxy, hook, and secret-boundary validation
• Azure Bicep compilation
• AWS and GCP OpenTofu validation
• Three-run live/published SRE benchmark verification
• Production container build