Align catalog with Bambu Lab product line, add conditional filters and admin sidebar

- Add master catalog (bambuLabCatalog.ts) as single source of truth for materials, finishes, colors, and refill/spool availability
- Fix incorrect finish-per-material mappings (remove PLA: 85A/90A/95A HF/FR/GF/HF, add ASA: Basic/CF/Aero, fix PETG/PC)
- Implement cascading filters on public site: material restricts finish, finish restricts color
- Add AdminSidebar component across all admin pages
- Redirect /upadaj to /dashboard when already authenticated
- Update color hex mappings and tests to match official Bambu Lab names

app/upadaj/customers/page.tsx

@@ -4,6 +4,7 @@ import { useState, useEffect, useCallback } from 'react';
 import { useRouter } from 'next/navigation';
 import { customerService } from '@/src/services/api';
 import { Customer, Sale } from '@/src/types/sales';
+import { AdminSidebar } from '@/src/components/AdminSidebar';
 
 interface CustomerWithSales extends Customer {
   sales?: Sale[];
@@ -172,50 +173,7 @@ export default function CustomersManagement() {
   return (
     <div className="min-h-screen bg-gray-50 dark:bg-gray-900 transition-colors">
       <div className="flex">
-        {/* Sidebar */}
-        <div className="w-64 bg-white dark:bg-gray-800 shadow-lg h-screen sticky top-0">
-          <div className="p-6">
-            <h2 className="text-xl font-bold text-gray-900 dark:text-white mb-6">Admin Panel</h2>
-            <nav className="space-y-2">
-              <a
-                href="/dashboard"
-                className="block px-4 py-2 text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 rounded"
-              >
-                Filamenti
-              </a>
-              <a
-                href="/upadaj/colors"
-                className="block px-4 py-2 text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 rounded"
-              >
-                Boje
-              </a>
-              <a
-                href="/upadaj/requests"
-                className="block px-4 py-2 text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 rounded"
-              >
-                Zahtevi za boje
-              </a>
-              <a
-                href="/upadaj/sales"
-                className="block px-4 py-2 text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 rounded"
-              >
-                Prodaja
-              </a>
-              <a
-                href="/upadaj/customers"
-                className="block px-4 py-2 bg-blue-100 dark:bg-blue-900 text-blue-700 dark:text-blue-300 rounded"
-              >
-                Kupci
-              </a>
-              <a
-                href="/upadaj/analytics"
-                className="block px-4 py-2 text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 rounded"
-              >
-                Analitika
-              </a>
-            </nav>
-          </div>
-        </div>
+        <AdminSidebar />
 
         {/* Main Content */}
         <div className="flex-1">