feat: add /clear command to TUI

cmd/sidekick-tui/main.go

@@ -58,6 +58,7 @@ type model struct {
   transientSteps   []string
   currentStream    string
   currentReasoning string
+  cancel           context.CancelFunc
   isThinking       bool
   err              error
   ready            bool
@@ -66,6 +67,17 @@ type model struct {
   renderer         *glamour.TermRenderer
 }
 
+func (m model) formatReasoning(reasoning string) string {
+  if reasoning == "" {
+    return ""
+  }
+  lines := strings.Split(strings.TrimSpace(reasoning), "\n")
+  for i, line := range lines {
+    lines[i] = "> " + line
+  }
+  return "> *Thinking:*\n>\n" + strings.Join(lines, "\n") + "\n"
+}
+
 type agentResponseMsg struct {
   response string
   err      error
@@ -211,7 +223,7 @@ func (m model) renderMessage(msg sidekick.Message) string {
 
   if m.renderer != nil {
     if reasoning != "" {
-      if r, err := m.renderer.Render("> *Thinking:*\n>\n> " + reasoning); err == nil {
+      if r, err := m.renderer.Render(m.formatReasoning(reasoning)); err == nil {
         reasoning = strings.TrimSpace(r) + "\n"
       }
     }
@@ -247,7 +259,7 @@ func (m *model) updateViewportContent() {
     reasoning := m.currentReasoning
     if m.renderer != nil {
       if reasoning != "" {
-        if r, err := m.renderer.Render("> *Thinking:*\n>\n> " + reasoning); err == nil {
+        if r, err := m.renderer.Render(m.formatReasoning(reasoning)); err == nil {
           reasoning = strings.TrimSpace(r) + "\n"
         }
       }
@@ -320,6 +332,20 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
         return m, nil
       }
 
+      trimmed := strings.TrimSpace(v)
+      if trimmed == "/clear" {
+        m.history = []sidekick.Message{
+          {Role: sidekick.MessageRoleSystem, Content: "Context cleared."},
+        }
+        m.currentStream = ""
+        m.currentReasoning = ""
+        m.transientSteps = nil
+        m.textarea.Reset()
+        m.updateViewportContent()
+        m.viewport.GotoBottom()
+        return m, nil
+      }
+
       m.history = append(m.history, sidekick.Message{
         Role:    sidekick.MessageRoleUser,
         Content: v,