Add bulk actions for contacts (delete, add to list, remove from list)

[falone]

Description:
Right now managing contacts in Notifuse is mostly done on a per‑contact basis. It would be very useful to have bulk actions for existing contacts, for example:

• Select multiple contacts and delete them at once.
• Select multiple contacts and add them to a list.
• Select multiple contacts and remove them from a list (not just unsubscribe via campaign, but directly from the list they’re in).

Use cases:

• Cleaning up outdated or test contacts in bulk.
• Migrating a group of users from one list to another (e.g., moving “beta users” to “main users”).
• Quickly removing all contacts from a specific list after a campaign or experiment.

Current limitations:

• Deleting contacts can only be done one by one via the “three dots” menu.
• There is no UI option to select multiple contacts and move them between lists or bulk‑remove them from a list.

Suggested UX:

• Checkboxes or “Select all” in the Contacts / Lists tables.
• A small action bar that appears when contacts are selected, with buttons like: “Delete selected contacts”, “Add selected contacts to list…”, “Remove selected contacts from list…”
• Optionally, show a confirmation modal before executing destructive actions (delete, remove from list).

If bulk actions are already planned or exist via API, it would be helpful to document this in the docs or add a small UI shortcut for power users.

[falone]

Update / Additional context:
I noticed that Notifuse already has a Bulk Update Contacts modal with CSV-based actions (Unsubscribe from list, Delete contacts) — great to see this exists!
However, I think it would be even more useful to support bulk actions directly from the Contacts table UI, without requiring a CSV file:

• Add checkboxes to the contacts table (or a "Select all" option)
• When one or more contacts are selected, show a small action bar with options:
  • Subscribe to list
  • Unsubscribe from list
  • Delete contacts
    This way, a user could simply filter or search for the contacts they need, select them, and perform the action in one click — without exporting/preparing a CSV just for contacts that already exist in the system.
    The CSV-based bulk modal could remain as-is for importing external contact lists. The checkbox-based approach would complement it for managing existing contacts inside Notifuse.