fix(greenhouse): remove whitespace below PluginNav in shell layout (#1549)

* fix(greenhouse): remove whitespace below PluginNav in shell layout

* chore(greenhouse): adds changeset

Author: ArtieReus

.changeset/public-weeks-act.md

@@ -0,0 +1,5 @@
+---
+"@cloudoperators/juno-app-greenhouse": patch
+---
+
+Restructure ShellLayout to apply padding only to content area rather than the entire main container. This allows NotificationsContainer (demo banner) to stick to the top without padding while eliminating unwanted whitespace below PluginNav.

apps/greenhouse/src/components/layout/ShellLayout.tsx

@@ -19,20 +19,22 @@ const shellStyles = `
   min-w-0`
 
 const mainStyles = `
-  py-4
-  pl-4
   bg-theme-content-area-bg
-  h-full
   overflow-x-auto
-  min-w-0`
+  min-w-0
+  h-full`
+
+const contentStyles = `
+  py-4
+  pl-4`
 
 const ShellLayout = ({ children }: ShellLayoutProps) => {
   return (
     <div className={`greenhouse-shell ${shellStyles}`}>
       <PluginNav />
-      <div className="min-w-0">
+      <div className={`greenhouse-main ${mainStyles}`}>
         <NotificationsContainer />
-        <div className={`greenhouse-main ${mainStyles}`}>{children}</div>
+        <div className={contentStyles}>{children}</div>
       </div>
     </div>
   )