fix(tui): pin dialog select footer to bottom (#29878)

packages/opencode/src/cli/cmd/tui/ui/dialog-select.tsx

@@ -354,7 +354,7 @@ export function DialogSelect<T>(props: DialogSelectProps<T>) {
   const right = createMemo(() => visibleActions().filter((item) => item.side === "right"))
 
   return (
-    <box gap={1} paddingBottom={1}>
+    <box gap={1} paddingBottom={1} flexGrow={1}>
       <box paddingLeft={4} paddingRight={4}>
         <box flexDirection="row" justifyContent="space-between">
           <text fg={theme.text} attributes={TextAttributes.BOLD}>
@@ -391,6 +391,7 @@ export function DialogSelect<T>(props: DialogSelectProps<T>) {
           </box>
         </Show>
       </box>
+      <box flexGrow={1} flexShrink={1}>
         <Show
           when={grouped().length > 0}
           fallback={
@@ -491,6 +492,7 @@ export function DialogSelect<T>(props: DialogSelectProps<T>) {
             </For>
           </scrollbox>
         </Show>
+      </box>
       <Show when={visibleActions().length} fallback={<box flexShrink={0} />}>
         <box
           paddingRight={2}