Configure S3-compatible object storage

Hive server can now be configured to use S3-compatible object storage by setting HIVE_OBJECT_STORAGE_PROVIDER=s3 and supplying the required S3 environment variables. New Hive.ObjectStorage helpers validate the required credentials and do not return secrets in public configuration. Helm defaults and Tuist production External Secrets mappings are wired to the hive-object-storage 1Password item, and the self-hosted S3 environment variables and Helm setup flow are documented.