docs(backup): documented cozy-default endpoint override via cozystack-platform Package has no effect #3245

Summary

docs/operations/backup-classes.md documents overriding the cozy-default backup S3 coordinates (backupStorage.endpoint, region, systemSecretName, etc.) by setting spec.components.backupstrategy-controller.values on the Package cozystack.cozystack-platform CR. This override has no effect: the platform chart never propagates those values to the backupstrategy-controller component, so an admin cannot point the default backup flow at an external or TLS S3 endpoint through the documented path.

Evidence

• Documented override (does not work): docs/operations/backup-classes.md (section "Admin overrides for cozy-default") instructs:

  kind: Package
  metadata:
    name: cozystack.cozystack-platform
  spec:
    components:
      backupstrategy-controller:
        values:
          backupStorage:
            endpoint: ...

• The cozystack.cozystack-platform Package exposes exactly one component, platform (the platform chart itself), see packages/core/installer/example/platform.yaml (spec.components.platform.values). There is no backupstrategy-controller component under this PackageSource, so the operator silently ignores it.
• The platform chart renders the child Package cozystack.backupstrategy-controller via the cozystack.platform.package.default helper with no components argument: packages/core/platform/templates/bundles/system.yaml ({{include "cozystack.platform.package.default" (list "cozystack.backupstrategy-controller" $) }}).
• packages/core/platform/templates/_helpers.tpl: the .default helper calls cozystack.platform.package with only three positional args, so $components stays empty and the rendered child Package omits spec.components entirely ({{- if $components }} gate). Nothing in the platform chart reads .Values.components.backupstrategy-controller.

Impact

• Admins running against an external S3 or the in-cluster TLS SeaweedFS cannot set backupStorage.endpoint (or region / systemSecretName) through the documented supported override path.
• The only working override is patching the child Package cozystack.backupstrategy-controller with spec.components.backupstrategy-controller.values (the operator does read child-Package components), but this is undocumented, and the platform helm-reconcile re-renders that child Package without a components block, risking that admin patch being reverted.

Proposed fix

Pick one:

• Wire the platform chart to pass a backupstrategy-controller components block (analogous to how monitoring-agents is rendered via cozystack.platform.package with an explicit components dict) so spec.components.backupstrategy-controller.values on the cozystack-platform Package actually reaches the child HelmRelease; or
• Correct the documentation to point at the child Package cozystack.backupstrategy-controller override path, and confirm that path survives platform helm-reconcile (protect it from being pruned by the empty components re-render).