feat(tui): add toggle to hide session header (#13244)

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -149,6 +149,7 @@ export function Session() {
   const [showDetails, setShowDetails] = kv.signal("tool_details_visibility", true)
   const [showAssistantMetadata, setShowAssistantMetadata] = kv.signal("assistant_metadata_visibility", true)
   const [showScrollbar, setShowScrollbar] = kv.signal("scrollbar_visible", false)
+  const [showHeader, setShowHeader] = kv.signal("header_visible", true)
   const [diffWrapMode] = kv.signal<"word" | "none">("diff_wrap_mode", "word")
   const [animationsEnabled, setAnimationsEnabled] = kv.signal("animations_enabled", true)
 
@@ -582,6 +583,15 @@ export function Session() {
         dialog.clear()
       },
     },
+    {
+      title: showHeader() ? "Hide header" : "Show header",
+      value: "session.toggle.header",
+      category: "Session",
+      onSelect: (dialog) => {
+        setShowHeader((prev) => !prev)
+        dialog.clear()
+      },
+    },
     {
       title: "Page up",
       value: "session.page.up",
@@ -963,7 +973,7 @@ export function Session() {
       <box flexDirection="row">
         <box flexGrow={1} paddingBottom={1} paddingTop={1} paddingLeft={2} paddingRight={2} gap={1}>
           <Show when={session()}>
-            <Show when={!sidebarVisible() || !wide()}>
+            <Show when={showHeader() && (!sidebarVisible() || !wide())}>
               <Header />
             </Show>
             <scrollbox