fix(codebase): freeze header name on scroll and remove count pill

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

@@ -260,7 +260,7 @@ function RailGroup({
     <div style={railGroup}>
       <header style={railGroupHeader}>
         <span style={railGroupTitle}>{title}</span>
-        <span style={countPill}>{count}</span>
+        {/* <span style={countPill}>{count}</span> */}
       </header>
       <div style={railItems}>{children}</div>
     </div>
@@ -382,7 +382,6 @@ const leftCol: React.CSSProperties = {
   flexDirection: "column",
   gap: 24,
   borderRight: `1px solid ${THEME.borderSoft}`,
-  padding: "20px",
   overflowY: "auto",
 };
 
@@ -406,7 +405,11 @@ const railGroupHeader: React.CSSProperties = {
   display: "flex",
   alignItems: "center",
   justifyContent: "space-between",
-  paddingBottom: 12,
+  padding: "20px 20px 12px 20px",
+  position: "sticky",
+  top: 0,
+  background: THEME.cardBg,
+  zIndex: 10,
 };
 const railGroupTitle: React.CSSProperties = {
   fontSize: "0.95rem",
@@ -424,7 +427,8 @@ const countPill: React.CSSProperties = {
 const railItems: React.CSSProperties = {
   display: "flex",
   flexDirection: "column",
-  gap: 10,
+  gap: 4,
+  padding: "0 20px 20px 20px",
 };
 const railEmpty: React.CSSProperties = {
   padding: "10px 12px",