feat: full mobile responsive optimization for Android/iPhone

- Add bottom navigation bar (6 tabs) for mobile, hidden on desktop
- Compact header with smaller logo and reduced padding on mobile
- Collapsible filter bar with active filter count badge on mobile
- Bottom-sheet style dropdowns with overlay and larger touch targets
- Fullscreen AI chat on mobile, floating window on desktop
- Responsive dashboard cards with always-visible expand button
- Smaller table text and touch-friendly scroll on all data grids
- iPhone safe-area support and thinner scrollbars on mobile

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

components/AIChat.tsx

@@ -93,21 +93,21 @@ const AIChat: React.FC<AIChatProps> = ({ onSendMessage, isOpen, setIsOpen }) =>
 
   return (
     <>
-      {/* Trigger Button */}
+      {/* Trigger Button - above bottom nav on mobile */}
       <button
         onClick={() => setIsOpen(!isOpen)}
-        className={`fixed bottom-6 right-6 z-50 p-4 rounded-full shadow-2xl transition-all duration-300 hover:scale-110 
+        className={`fixed bottom-20 right-4 md:bottom-6 md:right-6 z-50 p-3 md:p-4 rounded-full shadow-2xl transition-all duration-300 hover:scale-110
           ${isOpen ? 'bg-slate-700 rotate-90 opacity-0 pointer-events-none' : 'bg-primary text-white rotate-0 opacity-100'}`}
       >
         <ChatIcon />
       </button>
 
-      {/* Chat Window */}
+      {/* Chat Window - fullscreen on mobile, floating on desktop */}
       <div
-        className={`fixed z-50 bg-slate-900 border border-border shadow-2xl transition-all duration-300 flex flex-col overflow-hidden
+        className={`fixed z-[60] bg-slate-900 border border-border shadow-2xl transition-all duration-300 flex flex-col overflow-hidden
         ${isOpen
-            ? 'bottom-6 right-6 w-96 h-[600px] rounded-2xl opacity-100 translate-y-0'
-            : 'bottom-6 right-6 w-96 h-0 opacity-0 translate-y-10 pointer-events-none'}`}
+            ? 'inset-0 rounded-none md:inset-auto md:bottom-6 md:right-6 md:w-96 md:h-[600px] md:rounded-2xl opacity-100 translate-y-0'
+            : 'bottom-0 right-0 w-full h-0 md:bottom-6 md:right-6 md:w-96 opacity-0 translate-y-10 pointer-events-none'}`}
       >
         {/* Header */}
         <div className="bg-primary/10 p-4 border-b border-border flex justify-between items-center backdrop-blur">