Fix kanban multiline card persistence

internal/block/kanban.go

@@ -51,6 +51,10 @@ func ParseKanban(body string) []KanbanColumn {
 	for _, raw := range strings.Split(body, "\n") {
 		line := strings.TrimRight(raw, " \t")
 		if line == "" {
+			if lastCard != nil && raw != "" {
+				lastCard.Text += "\n"
+				continue
+			}
 			lastCard = nil // blank line breaks card continuation
 			continue
 		}

internal/block/kanban_test.go

@@ -160,6 +160,24 @@ func TestKanbanMultilineCardRoundTrip(t *testing.T) {
 	}
 }
 
+func TestKanbanMultilineCardWithBlankLineRoundTrip(t *testing.T) {
+	cols := []KanbanColumn{{Title: "Todo", Cards: []KanbanCard{
+		{Text: "First line\n\nThird line"},
+		{Text: "next card"},
+	}}}
+	md := SerializeKanban(cols)
+	got := ParseKanban(md)
+	if len(got) != 1 || len(got[0].Cards) != 2 {
+		t.Fatalf("shape lost: %+v", got)
+	}
+	if got[0].Cards[0].Text != "First line\n\nThird line" {
+		t.Errorf("blank-line text lost: %q", got[0].Cards[0].Text)
+	}
+	if got[0].Cards[1].Text != "next card" {
+		t.Errorf("second card = %+v", got[0].Cards[1])
+	}
+}
+
 func TestKanbanDoneColumnAutoMarks(t *testing.T) {
 	cols := []KanbanColumn{
 		{Title: "Done", Cards: []KanbanCard{{Text: "shipped"}}},

internal/editor/kanban_test.go

@@ -452,6 +452,32 @@ func TestKanbanPasteIntoCardEdit(t *testing.T) {
 	}
 }
 
+func TestKanbanCardBlankLineSurvivesFocusAwayAndBack(t *testing.T) {
+	md := sampleKanbanMD + "\n\nbelow"
+	m := New(Config{Title: "test", Content: md, Save: func(string) error { return nil }})
+	out, _ := m.Update(tea.WindowSizeMsg{Width: 120, Height: 40})
+	m = out.(Model)
+
+	idx := firstKanban(m)
+	if idx < 0 || m.kanban == nil {
+		t.Fatalf("kanban not initialized")
+	}
+	m.kanban.col = 0
+	m.kanban.card = 0
+	m = pressKey(m, "enter")
+	if !m.kanban.edit {
+		t.Fatalf("enter should put us in edit mode")
+	}
+	m.kanban.editTA.SetValue("First line\n\nThird line")
+
+	m.focusBlock(idx + 1)
+	m.focusBlock(idx)
+
+	if c := m.kanban.selectedCard(); c == nil || c.Text != "First line\n\nThird line" {
+		t.Fatalf("card text after focus round-trip = %+v", c)
+	}
+}
+
 func TestKanbanSwallowsPlainPrintableKeys(t *testing.T) {
 	// In selection mode, typing a plain printable character (one with no
 	// modifier) must NOT mutate the underlying textarea — that would