[EItanya]

Step 3 of the installer refinement, before the config becomes a library API.

Before this change, s3 and gcs installs needed raw chart values in three places: objectStore.* on substrate-atelet, and ateApi.snapshotLocation and objectStorePlugin.* on substrate. objectStore now also takes a struct, and the installer turns it into those values:

postgres:
  type: external        # or bundled
objectStore:
  type: s3              # or bundled, gcs
  bucket: my-snapshots
  s3: {region: us-east-1, endpoint: https://s3.example.com, pathStyle: true, credentialsSecret: s3-creds}

This also fixes a gap. With s3, the substrate release's object store plugin had only the backend name and no region, endpoint or credentials. It now gets them as objectStorePlugin.extraEnv, added after any entries the user set.

The second commit makes both dependencies take the same shape. Each is a struct with a type, and bundled means the installer deploys it. The installer's RustFS is now objectStore: bundled.

Existing configs stay valid:

• postgres: external and objectStore: s3 still parse as just the type.
• rustfs still parses, as bundled.
• Raw chart values still work.

The wizard asks for the bucket and the S3 or GCS settings instead of a values file.

I wrote this with Claude Code and reviewed the diff.