fix: 对齐 AGC 输入区 @ 与发送按钮

- 覆盖直接 Codex 输入区的全局按钮绝对定位

- @ 按钮改为 actions 容器内静态网格项，与发送按钮保持同一基线

apps/ai-game-creator-shell/src/styles.css

@@ -9098,16 +9098,27 @@ iframe.preview-frame {
   position: absolute;
   right: 48px;
   bottom: 10px;
+  display: flex;
+  align-items: center;
+  height: 30px;
 }
 
 .game-workbench-chat
   .project-supervisor-surface.is-direct-codex
   .project-supervisor-composer
   .resource-reference-input-at {
+  position: static !important;
+  right: auto !important;
+  bottom: auto !important;
+  display: grid;
   width: 30px;
+  min-width: 30px;
   height: 30px;
+  min-height: 30px;
+  padding: 0;
   border: 0;
   border-radius: 9px;
   background: var(--platform-button-primary-fill);
   color: var(--platform-button-primary-text);
+  place-items: center;
 }