feat(auth): implement option 3 architecture - server InteractiveServer login + client WASM dashboard

- Add Server.AddInteractiveServerComponents() + AddInteractiveServerRenderMode()
- Create Server AuthLayout for login form (MudBlazor)
- Implement LoginSimple.razor with @rendermode InteractiveServer in Server project
- Update App.razor: CascadingAuthenticationState + Router with AppAssembly=Server
- Fix Client MudBlazor Providers in MainLayout + AuthLayout
- Update Playwright tests: use dynamic selectors for MudTextField (auto-generated IDs)
- Build: 0 errors, 0 warnings
- API: /api/auth/login fully operational (200 OK confirmed)
- Playwright E2E test: 1 passed

Architecture:
/login    → Server InteractiveServer (MudBlazor form)
/         → Client WebAssembly (Dashboard)
/api/*    → Server Endpoints

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

tests/e2e/detailed-debug.spec.ts

@@ -0,0 +1,74 @@
+import { test } from '@playwright/test';
+
+test('상세 디버깅 - onclick 확인', async ({ page }) => {
+  console.log('\n╔════════════════════════════════════════════════════╗');
+  console.log('║        상세 디버깅 - Blazor 상호작용 확인        ║');
+  console.log('╚════════════════════════════════════════════════════╝\n');
+
+  // 네트워크 추적
+  page.on('request', request => {
+    console.log(`📤 [REQUEST] ${request.method()} ${request.url()}`);
+  });
+
+  page.on('response', response => {
+    console.log(`📥 [RESPONSE] ${response.status()} ${response.url()}`);
+  });
+
+  // 콘솔 추적
+  page.on('console', msg => {
+    if (msg.type() === 'log') {
+      console.log(`🖨️  [LOG] ${msg.text()}`);
+    } else if (msg.type() === 'error') {
+      console.log(`❌ [ERROR] ${msg.text()}`);
+    }
+  });
+
+  console.log('1️⃣ 페이지 접근...');
+  await page.goto('http://localhost:5265/login');
+  await page.waitForLoadState('networkidle');
+  await page.waitForTimeout(2000);
+
+  console.log('\n2️⃣ 버튼 onclick 핸들러 확인...');
+  const loginButton = page.locator('button:has-text("로그인")');
+
+  const onclickCheck = await loginButton.evaluate((el: any) => {
+    console.log('Button element:', el);
+    console.log('onclick:', el.onclick);
+    console.log('data attributes:', Array.from(el.attributes).map((a: any) => `${a.name}=${a.value}`));
+    return {
+      onclick: el.onclick,
+      onclickString: el.onclick?.toString() || 'null',
+      attributes: Array.from(el.attributes).map((a: any) => `${a.name}=${a.value}`),
+    };
+  });
+
+  console.log('   onclick 확인 결과:');
+  console.log(`   - onclick: ${onclickCheck.onclick}`);
+  console.log(`   - 속성 목록:`);
+  onclickCheck.attributes.forEach((attr: string) => {
+    console.log(`     • ${attr}`);
+  });
+
+  console.log('\n3️⃣ 입력 필드 확인...');
+  const usernameInput = page.locator('input[type="text"]').first();
+  const passwordInput = page.locator('input[type="password"]');
+
+  await usernameInput.fill('admin');
+  await passwordInput.fill('admin');
+  console.log('   입력 완료');
+
+  console.log('\n4️⃣ 버튼 클릭...');
+  await loginButton.click();
+  console.log('   클릭됨');
+
+  await page.waitForTimeout(3000);
+
+  console.log('\n5️⃣ 최종 상태...');
+  const finalUrl = page.url();
+  console.log(`   URL: ${finalUrl}`);
+
+  // 버튼 상태 재확인
+  const isVisible = await loginButton.isVisible();
+  const isEnabled = await loginButton.isEnabled();
+  console.log(`   버튼 시각성: ${isVisible}, 활성화: ${isEnabled}`);
+});