fix: ensure mobile menu and language dropdown appear in front of hero banner video (raised z-indexes for overlays)

- Navbar: z-[999]
- Mobile menu container/panel: z-[1000]/z-[1001]
- Cart drawer: z-[980]/z-[990]
- LanguageSwitcher dropdown/backdrop: z-[1010]/z-[1020]
- Updated comments
- Mobile menu (incl. when clicking language inside it) now reliably stacks above the mobile banner video and other content.

components/CartDrawer.tsx

@@ -11,7 +11,7 @@
  * KEY DESIGN CHOICES:
  * - Fixed position, full-height, max-w-md (beautiful on both mobile and desktop)
  * - Backdrop click closes it (standard mobile pattern)
- * - z-[70] sits above almost everything (including the sticky category nav)
+ * - z-[990] sits above almost everything (including the sticky category nav) (below mobile menu)
  * - All cart mutations go through the context — this component is "dumb" UI only
  * 
  * THE ORDERING FLOW (very important for restaurant context):
@@ -82,13 +82,13 @@ Thank you!`;
       {/* SEMI-TRANSPARENT BACKDROP */}
       {/* Clicking anywhere outside the drawer closes it (standard mobile pattern) */}
       <div 
-        className="fixed inset-0 bg-black/40 z-[60]" 
+        className="fixed inset-0 bg-black/40 z-[980]" 
         onClick={closeCart}
       />
 
       {/* THE ACTUAL DRAWER — slides in from right */}
-      {/* z-[70] ensures it sits above sticky nav, category pills, and most other UI */}
-      <div className="fixed top-0 right-0 h-full w-full max-w-md bg-[#F8F5F0] z-[70] shadow-2xl flex flex-col">
+      {/* z-[990] ensures it sits above sticky nav, category pills, and most other UI (below mobile menu) */}
+      <div className="fixed top-0 right-0 h-full w-full max-w-md bg-[#F8F5F0] z-[990] shadow-2xl flex flex-col">
         {/* HEADER — Title + item count + quick clear + close button */}
         <div className="flex items-center justify-between p-6 border-b border-[#EDE6D9]">
           <div className="flex items-center gap-3">