fix: remove [Authorize] from Dashboard, add internal auth check

Root cause: [Authorize] attribute was blocking /dashboard access before
Blazor auth state could be established, causing redirect to /not-found.

Solution:
- Remove [Authorize] from Dashboard.razor
- Add authentication check in OnInitializedAsync
- If not authenticated, redirect to login internally
- Reduced wait time from 6s to 3s in login.html

This allows:
1. /dashboard to load immediately
2. Blazor auth state to initialize
3. Dashboard to verify user is authenticated
4. Redirect to login if not authenticated

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

full-login-test.mjs

@@ -0,0 +1,95 @@
+import { chromium } from "@playwright/test";
+
+(async () => {
+  console.log("=== FULL LOGIN FLOW TEST WITH DETAILED LOGGING ===\n");
+  
+  const b = await chromium.launch({ 
+    headless: false,  // 브라우저 화면 표시
+    args: ["--disable-blink-features=AutomationControlled"]
+  });
+  
+  const p = await b.newPage();
+  
+  // 모든 콘솔 메시지 캡처
+  p.on("console", msg => {
+    const type = msg.type();
+    const text = msg.text();
+    console.log(`  [BROWSER-${type.toUpperCase()}] ${text}`);
+  });
+  
+  // 모든 요청/응답 로그
+  p.on("request", req => {
+    if (req.url().includes("auth")) {
+      console.log(`  [REQUEST] ${req.method()} ${req.url()}`);
+    }
+  });
+  
+  p.on("response", res => {
+    if (res.url().includes("auth")) {
+      console.log(`  [RESPONSE] ${res.status()} ${res.url()}`);
+    }
+  });
+  
+  try {
+    console.log("1️⃣  STEP 1: Loading login page...");
+    await p.goto("http://localhost:5265/login.html", { waitUntil: "networkidle" });
+    console.log("   ✓ Page loaded\n");
+    
+    console.log("2️⃣  STEP 2: Filling form (admin/admin)...");
+    const userInput = await p.$("input[name='username']");
+    if (!userInput) {
+      console.log("   ✗ Username input NOT FOUND");
+      console.log("   Page content snippet:");
+      const html = await p.content();
+      const snippet = html.substring(0, 500);
+      console.log(snippet);
+    } else {
+      await p.fill("input[name='username']", "admin");
+      await p.fill("input[name='password']", "admin");
+      console.log("   ✓ Form filled\n");
+      
+      console.log("3️⃣  STEP 3: Clicking login button...");
+      await p.click("button[type='submit']");
+      console.log("   ✓ Button clicked\n");
+      
+      console.log("4️⃣  STEP 4: Waiting 7 seconds for auth flow...");
+      for (let i = 1; i <= 7; i++) {
+        await new Promise(r => setTimeout(r, 1000));
+        const url = p.url();
+        console.log(`   [${i}s] Current URL: ${url}`);
+      }
+      
+      console.log("\n5️⃣  FINAL RESULT:");
+      const finalUrl = p.url();
+      const finalContent = await p.content();
+      
+      console.log(`   URL: ${finalUrl}`);
+      
+      if (finalUrl.includes("/dashboard")) {
+        if (finalContent.includes("관리자 대시보드")) {
+          console.log("   ✓✓✓ SUCCESS! Dashboard loaded with content!");
+        } else if (finalContent.includes("Not Found")) {
+          console.log("   ✗ Dashboard URL but 'Not Found' error");
+        } else {
+          console.log("   ✓ Dashboard page (content varies)");
+        }
+      } else if (finalUrl.includes("/not-found")) {
+        console.log("   ✗ FAILED: Redirected to /not-found");
+        console.log("   This means authentication failed");
+      } else if (finalUrl.includes("/login")) {
+        console.log("   ✗ Back at login page");
+      } else {
+        console.log("   ? Other page");
+      }
+      
+      // 스크린샷 저장
+      await p.screenshot({ path: "./playwright-test-result.png", fullPage: true });
+      console.log("\n📷 Screenshot saved: playwright-test-result.png");
+    }
+    
+  } catch (e) {
+    console.error("❌ Error:", e.message);
+  } finally {
+    await b.close();
+  }
+})();