fix(codebase): perfectly align left file tree header and right preview header

vibn-frontend/app/[workspace]/project/[projectId]/(home)/code/page.tsx

@@ -408,11 +408,13 @@ const railGroupHeader: React.CSSProperties = {
   display: "flex",
   alignItems: "center",
   justifyContent: "space-between",
-  padding: "20px 20px 12px 20px",
+  padding: "10px 20px",
   position: "sticky",
   top: 0,
   background: THEME.cardBg,
   zIndex: 10,
+  height: "41px",
+  boxSizing: "border-box",
 };
 const railGroupTitle: React.CSSProperties = {
   fontSize: "0.95rem",

vibn-frontend/components/project/gitea-file-viewer.tsx

@@ -154,6 +154,8 @@ export function GiteaFileViewer({ projectId, path }: GiteaFileViewerProps) {
           padding: "10px 16px",
           background: THEME.subtleBg,
           borderBottom: `1px solid ${THEME.borderSoft}`,
+          height: "41px",
+          boxSizing: "border-box",
         }}
       >
         <div
@@ -270,6 +272,8 @@ function Centered({
           padding: "10px 16px",
           background: THEME.subtleBg,
           borderBottom: `1px solid ${THEME.borderSoft}`,
+          height: "41px",
+          boxSizing: "border-box",
         }}
       >
         <div