Implement opt-out of automated updates from the Software Center UI

[DavidePrincipi]

In a cluster with an active Subscription, overnight automatic application updates are always enabled. Opting out is currently possible only through CLI commands, which is not discoverable and error-prone for administrators. The purpose of this feature is to expose the opt-out choice directly in the Software Center UI, implementing the approved design from #7976.

Proposed solution

Implement the UI approved in the design issue #7976 (Figma mockups):

• Add global actions to enable/disable automatic application updates from Software Center > Updates
• Add per-application enable/disable automatic updates actions from:
  • Software Center > Installed
  • Applications section
• Add inline notifications reflecting the global automatic updates status
• Add an "Updates disabled" status tag for applications excluded from automatic updates
• Update empty states and related screens
• Replace all "instance" and "apps" labels with "applications"
• Add dedicated community states without automatic updates controls (automatic updates are a Subscription feature)

Alternative solutions

Keep the current CLI-only opt-out procedure. Discarded: it is undocumented for most administrators and does not fit the Software Center user experience.

Additional context

The design work, mockups, and review discussion are in #7976 (approved by @DavidePrincipi and @andre8244).

See also

• Design issue: Switch-off automated updates in Software Center #7976
• Figma mockups: https://www.figma.com/design/OsYqPXdkKJz0tBJRsiQgAf/NethServer-shared-file?node-id=4543-16705
• Discussion (planning) https://mattermost.nethesis.it/nethesis/pl/hya7yazcrfbwud5p8ytyaywtbo

[DavidePrincipi]

@stephdl I started the backend implementation in branch feat-8101, you can open a PR directly on it if you like. https://github.com/NethServer/ns8-core/tree/feat-8101

Backend: automatic update policy (global + per-instance) NethServer/ns8-core@8bc8568

list-modules output now includes, for each app:

• apply_updates_is_active (bool) — cluster-wide automatic updates switch
• subscription_is_active (bool) — whether a Nethesis subscription is active (use this to show/hide the
  automatic-updates UI, since the feature only works with a subscription)
• per installed instance, installed[].automatic_updates (bool) — whether that specific instance is opted
  into automatic updates (default true)

New action to change both: set-automatic-updates

{
  "apply_updates_is_active": false,
  "instances": { "dokuwiki1": false, "dokuwiki2": true }
}

Both fields are optional — send only what changed. Unknown instance IDs return a validation-failed error
(instance_not_found).

Notes:

• Automatically-run updates (nightly apply-updates timer) skip instances with automatic_updates: false;
  manual/UI-triggered updates always apply regardless of the policy.
• Toggling apply_updates_is_active also re-syncs the systemd apply-updates.timer on the backend — no
  extra call needed from the frontend.

Docs: docs/core/updates.md, docs/core/database.md (cluster/module_automatic_update key).