tui: improve responsive layout by hiding header/footer when sidebar is visible (#7365)

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

@@ -887,7 +887,7 @@ 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()}>
+            <Show when={!sidebarVisible() || !wide()}>
               <Header />
             </Show>
             <scrollbox
@@ -1028,9 +1028,6 @@ export function Session() {
                 sessionID={route.sessionID}
               />
             </box>
-            <Show when={!sidebarVisible()}>
-              <Footer />
-            </Show>
           </Show>
           <Toast />
         </box>