fix(tui): constrain autocomplete height to available screen space (#7181)

packages/opencode/src/cli/cmd/tui/component/prompt/autocomplete.tsx

@@ -653,8 +653,10 @@ export function Autocomplete(props: {
   })
 
   const height = createMemo(() => {
-    if (options().length) return Math.min(10, options().length)
-    return 1
+    const count = options().length || 1
+    if (!store.visible) return Math.min(10, count)
+    positionTick()
+    return Math.min(10, count, Math.max(1, props.anchor().y))
   })
 
   let scroll: ScrollBoxRenderable