fix(tui): add extra newline after thinking block for better readability

cmd/sidekick-tui/main.go

@@ -245,7 +245,7 @@ func (m model) renderMessage(msg sidekick.Message) string {
   if m.renderer != nil {
     if reasoning != "" {
       if r, err := m.renderer.Render(m.formatReasoning(reasoning)); err == nil {
-        reasoning = strings.TrimSpace(r) + "\n"
+        reasoning = strings.TrimSpace(r) + "\n\n"
       }
     }
     if content != "" {
@@ -281,7 +281,7 @@ func (m *model) updateViewportContent() {
     if m.renderer != nil {
       if reasoning != "" {
         if r, err := m.renderer.Render(m.formatReasoning(reasoning)); err == nil {
-          reasoning = strings.TrimSpace(r) + "\n"
+          reasoning = strings.TrimSpace(r) + "\n\n"
         }
       }
       if content != "" {

cmd/sidekick-tui/repro_test.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+  "strings"
+  "testing"
+
+  "github.com/charmbracelet/glamour"
+  "sidekick"
+)
+
+func TestRenderMessageNewlines(t *testing.T) {
+  r, _ := glamour.NewTermRenderer(
+    glamour.WithStandardStyle("dark"),
+    glamour.WithWordWrap(80),
+  )
+  m := model{renderer: r}
+
+  msg := sidekick.Message{
+    Role:    sidekick.MessageRoleUser,
+    Content: "Line 1\nLine 2",
+  }
+
+  rendered := m.renderMessage(msg)
+  if !strings.Contains(rendered, "Line 1") || !strings.Contains(rendered, "Line 2") {
+    t.Errorf("rendered message missing content: %s", rendered)
+  }
+
+  // Check if newline is preserved. If squashed, it might be "Line 1 Line 2"
+  if strings.Contains(rendered, "Line 1 Line 2") {
+    t.Error("newlines were squashed in user message")
+  }
+}
+
+func TestRenderMessageReasoningGap(t *testing.T) {
+  r, _ := glamour.NewTermRenderer(
+    glamour.WithStandardStyle("dark"),
+    glamour.WithWordWrap(80),
+  )
+  m := model{renderer: r}
+
+  msg := sidekick.Message{
+    Role:      sidekick.MessageRoleAssistant,
+    Reasoning: "Thinking about it",
+    Content:   "Actual response",
+  }
+
+  rendered := m.renderMessage(msg)
+  // Check if there is a gap between Thinking and Response
+  
+  if !strings.Contains(rendered, "Thinking") || !strings.Contains(rendered, "Actual") || !strings.Contains(rendered, "response") {
+    t.Errorf("rendered message missing content: %s", rendered)
+  }
+
+  // If there's no blank line between reasoning and content, they might be too close.
+  // We want to see if they are on adjacent lines or have a gap.
+  // The user says "next one begins immediately while it should start from a new line"
+  // This might mean it's on the SAME line if glamour messed up, or just next line.
+  
+  // Let's print it to see
+  t.Logf("Rendered Assistant:\n%s", rendered)
+}