feat: create Blazor-based login component with EmptyLayout

- Create Login.razor component at /login path with Blazor form
- Create EmptyLayout to prevent MainLayout wrapping on login page
- Update Program.cs to redirect unauthenticated users to /login (Blazor route)
- Integrate with CustomAuthenticationStateProvider for proper auth state management
- Handle authentication response and token storage

Note: Login flow still has routing issues - investigating dashboard redirect

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

test-login-final.mjs

@@ -0,0 +1,42 @@
+import { chromium } from '@playwright/test';
+
+(async () => {
+  const browser = await chromium.launch();
+  const page = await browser.newPage({ viewport: { width: 1280, height: 720 } });
+  
+  try {
+    await page.goto('http://localhost:5265/login');
+    console.log('✓ Login page loaded');
+    
+    // Check if Blazor component rendered
+    const content1 = await page.content();
+    if (content1.includes('관리자 아이디')) {
+        console.log('✓ Blazor login form rendered');
+    }
+    
+    // Fill credentials
+    await page.fill('input', 'admin');
+    const inputs = await page.$$('input[type="password"]');
+    if (inputs.length > 0) {
+        await inputs[0].fill('admin');
+    }
+    
+    await page.click('button[type="submit"]');
+    console.log('✓ Login submitted');
+    
+    // Wait for navigation
+    await page.waitForNavigation({ waitUntil: 'networkidle', timeout: 5000 });
+    
+    console.log('✓ Navigation complete');
+    console.log('  URL: ' + page.url());
+    
+    // Take screenshot
+    await page.screenshot({ path: './login-success.png', fullPage: true });
+    console.log('✓ Screenshot saved');
+    
+  } catch (e) {
+    console.error('Error:', e.message);
+  }
+  
+  await browser.close();
+})();