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.mjs

@@ -0,0 +1,42 @@
+import { chromium } from '@playwright/test';
+
+(async () => {
+  const browser = await chromium.launch();
+  const page = await browser.newPage();
+  
+  try {
+    await page.goto('http://localhost:5265/login');
+    console.log('✓ Loaded login page');
+    
+    // Fill and submit
+    await page.fill('input[type="text"]', 'admin');
+    await page.fill('input[type="password"]', 'admin');
+    await page.click('button[type="submit"]');
+    console.log('✓ Form submitted');
+    
+    // Wait for page load
+    await page.waitForNavigation({ waitUntil: 'load', timeout: 10000 });
+    
+    const url = page.url();
+    const content = await page.content();
+    
+    console.log('\nResult:');
+    console.log('  URL: ' + url);
+    
+    if (url.includes('/dashboard') && content.includes('관리자 대시보드')) {
+        console.log('✓ Dashboard successfully loaded!');
+    } else if (content.includes('Not Found')) {
+        console.log('✗ Error: Not Found');
+    } else {
+        console.log('  Status: Other');
+    }
+    
+    await page.screenshot({ path: './login-result.png', fullPage: true });
+    console.log('  Screenshot: login-result.png');
+    
+  } catch (e) {
+    console.error('Test failed:', e.message);
+  }
+  
+  await browser.close();
+})();