Manage notification channels instead of an ntfy topic

Mirrors the server's channels API: add/remove channels per user from the Users
section. Requires the matching server release.

Claude-Session: https://claude.ai/code/session_016mBLURvJoMuUEr9cB2RpUN

internal/tui/view.go

@@ -161,8 +161,12 @@ func (m Model) renderBody() string {
 		return m.renderTeamPicker()
 	case modeUserCreate:
 		return m.renderUserCreate()
-	case modeUserNotifyEdit:
-		return m.renderUserNotifyEdit()
+	case modeChannelMenu:
+		return m.renderChannelMenu()
+	case modeChannelAdd:
+		return m.renderChannelAdd()
+	case modeChannelRemoveByID:
+		return m.renderChannelRemoveByID()
 	case modeAPIKeyMenu:
 		return m.renderAPIKeyMenu()
 	case modeAPIKeyCreate:
@@ -222,8 +226,14 @@ func (m Model) renderFooter() string {
 	case modeUserCreate:
 		return withStatus("  tab·next field  enter·create  esc·cancel")
 
-	case modeUserNotifyEdit:
-		return withStatus("  enter·save  esc·cancel   (empty clears the topic)")
+	case modeChannelMenu:
+		return withStatus("  a·add a channel  r·remove by ID  esc·back")
+
+	case modeChannelAdd:
+		return withStatus("  enter·add  esc·back   (type:address)")
+
+	case modeChannelRemoveByID:
+		return withStatus("  enter·remove  esc·back")
 
 	case modeAPIKeyMenu:
 		return withStatus("  n·new key  r·revoke by ID  esc·back")
@@ -256,7 +266,7 @@ func (m Model) renderFooter() string {
 		case sectionSchedule:
 			return withStatus("  +·assign day  W·assign week  d·del  ←/→·shift week  " + m.teamHint() + "tab·section  r·refresh  q·quit")
 		case sectionUsers:
-			return withStatus("  n·new user  t·topic  d·delete  k·API keys  p·password  r·refresh  L·sign out  q·quit")
+			return withStatus("  n·new user  t·channels  d·delete  k·API keys  p·password  r·refresh  L·sign out  q·quit")
 		}
 		return "\n" + m.styles.Footer.Render(m.help.ShortHelpView(m.keys.ShortHelp()))
 	}
@@ -748,10 +758,10 @@ func eventLabel(e api.IncidentEvent) string {
 		return "  Resolved (all alerts stopped firing)"
 	case api.EventNotified:
 		// An empty username here is not "the server acted": it means the page
-		// went to the shared fallback topic, so it belongs to nobody.
+		// went to the shared fallback, so it belongs to nobody.
 		return fmt.Sprintf("  Notified %s%s", notifiedTarget(who), notifyKind(e.Detail))
 	case api.EventNotifyFailed:
-		// The detail is "<kind>: <reason>", and the reason is the point — it is
+		// The detail is "<kind> via <channel>: <reason>", and the reason is the point — it is
 		// the only thing that says why nobody's phone rang.
 		return truncate(fmt.Sprintf("  Notification to %s failed · %s",
 			notifiedTarget(who), e.Detail), 52)
@@ -767,11 +777,11 @@ func eventLabel(e api.IncidentEvent) string {
 }
 
 // notifiedTarget names who a page reached. The server attaches no user when it
-// published to the shared fallback topic, and saying so is the difference
+// published to the shared fallback, and saying so is the difference
 // between "somebody was paged" and "the on-call rota was empty".
 func notifiedTarget(username string) string {
 	if username == "" {
-		return "the fallback topic"
+		return "the fallback"
 	}
 	return username
 }
@@ -959,14 +969,44 @@ func (m Model) renderUserCreate() string {
 		emailLabel + m.userFormInputs[1].View() + "\n"
 }
 
-func (m Model) renderUserNotifyEdit() string {
-	header := fmt.Sprintf("\n  Push notifications for %s\n", m.styles.Bold.Render(m.selectedUser.Username))
+func (m Model) renderChannelMenu() string {
+	header := fmt.Sprintf("\n  Notification channels for %s\n\n", m.styles.Bold.Render(m.selectedUser.Username))
+	var list string
+	if len(m.selectedUser.Channels) == 0 {
+		list = line(m.styles.Muted, "  None — their incidents page the server's shared fallback,\n"+
+			"  which carries no Acknowledge button.")
+	}
+	for _, c := range m.selectedUser.Channels {
+		state := ""
+		if !c.Enabled {
+			state = "  (off)"
+		}
+		// The address is only sent to its owner; an administrator sees the kind.
+		address := c.Address
+		if address == "" {
+			address = "(address hidden)"
+		}
+		list += fmt.Sprintf("  %s  %s  %s%s\n", m.styles.Accent.Render(fmt.Sprintf("#%d", c.ID)), c.Type, address, state)
+	}
+	options := "\n" +
+		m.styles.Accent.Render("  a") + "  · add a channel (type:address, e.g. ntfy:my-topic)\n" +
+		m.styles.Accent.Render("  r") + "  · remove a channel by ID\n"
+	return header + list + options
+}
+
+func (m Model) renderChannelAdd() string {
+	header := fmt.Sprintf("\n  New channel for %s\n\n", m.styles.Bold.Render(m.selectedUser.Username))
 	hint := line(m.styles.Muted,
-		"  The ntfy topic this user's pages go to. Leave it empty to clear it —\n"+
-			"  their incidents then page the server's shared fallback topic, which\n"+
-			"  carries no Acknowledge button.")
-	label := m.styles.Selected.Render("  Topic:  ")
-	return header + "\n" + hint + "\n" + label + m.ntfyTopicInput.View() + "\n"
+		"  The kind of channel, a colon, then where it goes — for ntfy, the topic.\n"+
+			"  Only kinds the server has configured are accepted.")
+	label := m.styles.Selected.Render("  Channel:  ")
+	return header + hint + "\n" + label + m.channelAddInput.View() + "\n"
+}
+
+func (m Model) renderChannelRemoveByID() string {
+	header := fmt.Sprintf("\n  Remove a channel from %s\n\n", m.styles.Bold.Render(m.selectedUser.Username))
+	label := m.styles.Selected.Render("  Channel ID:  ")
+	return header + label + m.channelRemoveIn.View() + "\n"
 }
 
 func (m Model) renderPasswordSet() string {