Add Slack notifications for core VerifyWise events, with simple routing from each notification type to one or more Slack channels. No per user targeting for now, only channel based delivery. The Slack workspace is already connectable in Settings, so this issue focuses on routing UX, message content for Slack, and acceptance criteria.

Main goals are as follows:

• Let an organization admin map notification types to one or more Slack channels
• Use Slack friendly messages
• Add a Configure button in the Slack settings page that opens a drawer for mapping
• Provide "Send test" for each mapping, plus a default fallback channel

Out of scope items are direct messages to individual users.

UX, UI, and flows

Notification routing section

• Categories: Membership and roles, Policy reminders and status, Evidence and task alerts, Control or policy changes.
• A configure button that configures each category in the drawer (screenshot below).

Configure drawer

• This drawer will be used to configure the mapping between the notification and the Slack channel.
• Allow multiple channels per notification.
• Save Changes and Cancel.

Notification catalog

Variables in {curly}:

• Project created: *Project created* · {project_name} by {actor_name}
• User added as Project Admin: *Membership update* · {user_name} is now *Project Admin* on {project_name} (added by {actor_name})
• User added as Project Editor: *Membership update* · {user_name} is now *Project Editor* on {project_name} (added by {actor_name})
• User added as Project Reviewer: *Membership update* · {user_name} is now *Project Reviewer* on {project_name} (added by {actor_name})
• Role change to Admin: *Role change* · {user_name} is now *Project Admin* on {project_name} (changed by {actor_name})
• Policy due soon, still incomplete: *Policy due soon* · "{policy_name}" for {project_name} is due on {due_date} and is still incomplete Next steps: review evidence, assign editors, update status

Routing rules

• Each notification type can send to many channels.
• If a type has no mapping, that is ok.
• No user mentions for now.

Permissions and safeguards

• Admin only can edit mappings. This section can only be edited by admin. When another user type views this tabbar, we can show "You are not authorized to view this section."
• Show only channels the bot can post to. For private channels, prompt to invite the bot.
• Post as VerifyWise bot.
• Sends a sample message with fake variables to the selected channels and shows a success toast (the current test message sample can be used)
• A channel might be removed on Slack. In this case handle it gracefully.