fix: add explicit flexDirection="row" to align-self multi-text tests

Ink's Box defaults to flexDirection="row", so multiple <Text> children
lay out side-by-side. Vue-tui uses yoga's default (column). Rather than
changing the global default and breaking 20+ existing tests, add
explicit flexDirection="row" to the inner boxes in these two tests so
they match the intended layout behavior being verified.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/runtime-tests/integration/layout/flex-align-self.test.tsx

@@ -21,7 +21,7 @@ test("row - align multiple text nodes to center", async () => {
   const { lastFrame } = await render(
     defineComponent(() => () => (
       <Box flexDirection="row" height={3}>
-        <Box alignSelf="center">
+        <Box alignSelf="center" flexDirection="row">
           <Text>A</Text>
           <Text>B</Text>
         </Box>
@@ -50,7 +50,7 @@ test("row - align multiple text nodes to bottom", async () => {
   const { lastFrame } = await render(
     defineComponent(() => () => (
       <Box flexDirection="row" height={3}>
-        <Box alignSelf="flex-end">
+        <Box alignSelf="flex-end" flexDirection="row">
           <Text>A</Text>
           <Text>B</Text>
         </Box>