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/update_test.go

@@ -416,7 +416,7 @@ func TestSchedule_ReassigningAPartlyTakenWeekAsksOnce(t *testing.T) {
 	mustContain(t, m.confirmPrompt(), "2 of 7 days are assigned to niklas and sam")
 }
 
-// ── Ntfy topic ────────────────────────────────────────────────────────────
+// ── Notification channels ─────────────────────────────────────────────────
 
 // onUsers puts the model in the Users section with a loaded table.
 func onUsers(users []api.User) Model {
@@ -428,42 +428,96 @@ func onUsers(users []api.User) Model {
 }
 
 func userFixtures() []api.User {
-	topic := "terdut-niklas"
 	return []api.User{
-		{ID: 1, Username: "niklas", Email: "niklas@example.com", NtfyTopic: &topic},
+		{ID: 1, Username: "niklas", Email: "niklas@example.com",
+			Channels: []api.NotificationChannel{{ID: 3, Type: "ntfy", Address: "terdut-niklas", Enabled: true}}},
 		{ID: 2, Username: "alex", Email: "alex@example.com"},
 	}
 }
 
-func TestNotifyTopic_EditPrefillsTheCurrentTopic(t *testing.T) {
+func TestChannels_TOpensTheMenuForTheUserUnderTheCursor(t *testing.T) {
 	m, _ := press(t, onUsers(userFixtures()), "t")
 
-	if m.mode != modeUserNotifyEdit {
-		t.Fatalf("expected the topic editor, got mode %v", m.mode)
+	if m.mode != modeChannelMenu {
+		t.Fatalf("expected the channel menu, got mode %v", m.mode)
 	}
 	if m.selectedUser.ID != 1 {
 		t.Errorf("expected the user under the cursor, got %d", m.selectedUser.ID)
 	}
-	// Prefilled, so editing a topic does not mean retyping it from scratch.
-	if got := m.ntfyTopicInput.Value(); got != "terdut-niklas" {
-		t.Errorf("expected the current topic prefilled, got %q", got)
-	}
 }
 
-// A user with no topic opens an empty field rather than the previous user's.
-func TestNotifyTopic_EditStartsEmptyWhenUnset(t *testing.T) {
-	m := onUsers(userFixtures())
-	m, _ = press(t, m, "t")
+func TestChannels_AddStartsEmptyEveryTime(t *testing.T) {
+	m, _ := press(t, onUsers(userFixtures()), "t")
+	m, _ = press(t, m, "a")
+	if m.mode != modeChannelAdd {
+		t.Fatalf("expected the add form, got mode %v", m.mode)
+	}
+	m = typeInto(t, m, "ntfy:abandoned")
 	m, _ = press(t, m, "esc")
-	m.userManageTable.SetCursor(1)
+	if m.mode != modeChannelMenu {
+		t.Fatalf("escape should go back to the menu, got mode %v", m.mode)
+	}
 
-	m, _ = press(t, m, "t")
-	if got := m.ntfyTopicInput.Value(); got != "" {
-		t.Errorf("expected an empty field for a user with no topic, got %q", got)
+	m, _ = press(t, m, "a")
+	if got := m.channelAddInput.Value(); got != "" {
+		t.Errorf("expected an empty field, got %q", got)
 	}
 }
 
-func TestNotifyTopic_EscapeAbandonsWithoutSaving(t *testing.T) {
+func TestChannels_AddRejectsASpecWithoutTypeAndAddress(t *testing.T) {
+	for _, spec := range []string{"", "ntfy", "ntfy:", ":topic"} {
+		m, _ := press(t, onUsers(userFixtures()), "t")
+		m, _ = press(t, m, "a")
+		m.channelAddInput.SetValue(spec)
+
+		m, cmd := press(t, m, "enter")
+		if m.mode != modeChannelAdd {
+			t.Errorf("%q: expected to stay on the form, got mode %v", spec, m.mode)
+		}
+		if m.statusMsg == "" {
+			t.Errorf("%q: expected an explanation", spec)
+		}
+		_ = cmd // only the status-clearing tick
+	}
+}
+
+func TestChannels_AddSubmitsAndReturnsToTheDashboard(t *testing.T) {
+	m, _ := press(t, onUsers(userFixtures()), "t")
+	m, _ = press(t, m, "a")
+	m.channelAddInput.SetValue("ntfy:my-topic")
+
+	m, cmd := press(t, m, "enter")
+	if cmd == nil {
+		t.Fatal("expected adding a channel to call the server")
+	}
+	if m.mode != modeDashboard {
+		t.Errorf("expected a return to the dashboard, got mode %v", m.mode)
+	}
+}
+
+func TestChannels_RemoveNeedsAPositiveID(t *testing.T) {
+	m, _ := press(t, onUsers(userFixtures()), "t")
+	m, _ = press(t, m, "r")
+	if m.mode != modeChannelRemoveByID {
+		t.Fatalf("expected the remove form, got mode %v", m.mode)
+	}
+
+	for _, bad := range []string{"", "abc", "0", "-3"} {
+		m.channelRemoveIn.SetValue(bad)
+		next, _ := press(t, m, "enter")
+		if next.mode != modeChannelRemoveByID {
+			t.Errorf("%q: expected to stay on the form, got mode %v", bad, next.mode)
+		}
+	}
+
+	m.channelRemoveIn.SetValue("3")
+	m, cmd := press(t, m, "enter")
+	if cmd == nil || m.mode != modeDashboard {
+		t.Errorf("expected a valid ID to call the server and return, mode %v", m.mode)
+	}
+}
+
+func TestChannels_EscapeAbandonsWithoutSaving(t *testing.T) {
 	m, _ := press(t, onUsers(userFixtures()), "t")
 	m, cmd := press(t, m, "esc")
 
@@ -475,23 +529,7 @@ func TestNotifyTopic_EscapeAbandonsWithoutSaving(t *testing.T) {
 	}
 }
 
-// Clearing a topic is a real action, not a no-op: it is how a user is taken off
-// their own topic and back onto the shared fallback. Contrast the snooze prompt,
-// where an empty value means "I changed my mind".
-func TestNotifyTopic_EmptyInputStillSubmits(t *testing.T) {
-	m, _ := press(t, onUsers(userFixtures()), "t")
-	m.ntfyTopicInput.SetValue("")
-
-	m, cmd := press(t, m, "enter")
-	if cmd == nil {
-		t.Fatal("expected clearing the topic to call the server")
-	}
-	if m.mode != modeDashboard {
-		t.Errorf("expected a return to the dashboard, got mode %v", m.mode)
-	}
-}
-
-func TestNotifyTopic_IsUsersSectionOnly(t *testing.T) {
+func TestChannels_IsUsersSectionOnly(t *testing.T) {
 	m := sized()
 	m.activeSection = sectionIncidents
 	if next, cmd := press(t, m, "t"); cmd != nil || next.mode != modeDashboard {