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-flow.mjs

@@ -0,0 +1,44 @@
+import { chromium } from '@playwright/test';
+
+(async () => {
+  try {
+    const browser = await chromium.launch();
+    const page = await browser.newPage({ viewport: { width: 1280, height: 720 } });
+    
+    // Go to login page
+    await page.goto('http://localhost:5265/login');
+    console.log('Loaded login page');
+    
+    // Fill in credentials
+    await page.fill('input[name="username"]', 'admin');
+    await page.fill('input[name="password"]', 'admin');
+    
+    // Submit
+    await page.click('button[type="submit"]');
+    console.log('Submitted login form');
+    
+    // Wait for navigation
+    await page.waitForNavigation({ waitUntil: 'networkidle' });
+    console.log('Page navigated');
+    
+    // Check URL
+    console.log('Current URL: ' + page.url());
+    
+    // Check content
+    const content = await page.content();
+    if (content.includes('Not Found')) {
+        console.log('ERROR: Page shows Not Found');
+    } else if (content.includes('관리자 대시보드') || content.includes('Dashboard')) {
+        console.log('SUCCESS: Dashboard loaded');
+    } else {
+        console.log('Other content loaded');
+    }
+    
+    // Take screenshot
+    await page.screenshot({ path: './test-dashboard.png', fullPage: true });
+    
+    await browser.close();
+  } catch (e) {
+    console.error('Test failed:', e.message);
+  }
+})();