feat(frontend): Transform layout to use shadcn dashboard-01 with iOS PWA safe area support.

- Replace custom layout with modern SidebarProvider/SidebarInset structure
- Add AppSidebar component using shadcn patterns with preserved account summary
- Add SiteHeader component with SidebarTrigger integration
- Install shadcn sidebar, separator, and related UI components
- Fix iOS PWA safe area issues - sidebar no longer overlaps dynamic island/notch
- Add pt-safe-top and pl-safe-left classes to sidebar and header components
- Remove legacy Sidebar.tsx and Header.tsx components
- Preserve all existing functionality: navigation, API health status, theme toggle, PWA features
- Improve mobile responsive behavior with built-in shadcn drawer patterns

🤖 Generated with [Claude Code](https://claude.ai/code)

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

frontend/src/components/ui/input.tsx

@@ -1,6 +1,6 @@
-import * as React from "react";
+import * as React from "react"
 
-import { cn } from "@/lib/utils";
+import { cn } from "@/lib/utils"
 
 const Input = React.forwardRef<HTMLInputElement, React.ComponentProps<"input">>(
   ({ className, type, ...props }, ref) => {
@@ -9,14 +9,14 @@ const Input = React.forwardRef<HTMLInputElement, React.ComponentProps<"input">>(
         type={type}
         className={cn(
           "flex h-9 w-full rounded-md border border-input bg-transparent px-3 py-1 text-base shadow-sm transition-colors file:border-0 file:bg-transparent file:text-sm file:font-medium file:text-foreground placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50 md:text-sm",
-          className,
+          className
         )}
         ref={ref}
         {...props}
       />
-    );
-  },
-);
-Input.displayName = "Input";
+    )
+  }
+)
+Input.displayName = "Input"
 
-export { Input };
+export { Input }