fix: update E2E test API paths and payloads to match backend

- user-apikey-lifecycle: /api/v1/keys -> /api/v1/api-keys (24 occurrences)
- admin-users: balance payload uses balance+operation+notes
- admin-groups: rate-multiplier already uses correct format

tests/debug-login.js

@@ -0,0 +1,61 @@
+const { chromium } = require('@playwright/test');
+
+(async () => {
+  const browser = await chromium.launch({
+    headless: false,
+    executablePath: 'C:/Users/Admin/AppData/Local/ms-playwright/chromium-1208/chrome-win64/chrome.exe'
+  });
+  const context = await browser.newContext();
+  const page = await context.newPage();
+  
+  // Listen for console messages
+  page.on('console', msg => {
+    console.log('CONSOLE:', msg.type(), msg.text());
+  });
+  
+  // Listen for page errors
+  page.on('pageerror', error => {
+    console.log('PAGE ERROR:', error.message);
+  });
+  
+  try {
+    console.log('Navigating to login page...');
+    await page.goto('http://localhost:8080/login', { waitUntil: 'networkidle', timeout: 30000 });
+    
+    console.log('Waiting for app to load...');
+    await page.waitForTimeout(5000);
+    
+    // Get the app content
+    const appHtml = await page.locator('#app').innerHTML();
+    console.log('App HTML length:', appHtml.length);
+    console.log('App HTML preview:', appHtml.substring(0, 500));
+    
+    // Try to find email input
+    const emailInput = page.locator('#email');
+    const count = await emailInput.count();
+    console.log('Email input count:', count);
+    
+    if (count > 0) {
+      console.log('Email input is visible:', await emailInput.isVisible());
+    } else {
+      // Try generic selectors
+      const inputs = await page.locator('input').count();
+      console.log('Total input count:', inputs);
+      
+      const allInputs = await page.locator('input').all();
+      for (let i = 0; i < allInputs.length; i++) {
+        const input = allInputs[i];
+        const id = await input.getAttribute('id');
+        const type = await input.getAttribute('type');
+        const placeholder = await input.getAttribute('placeholder');
+        console.log(`Input ${i}: id=${id}, type=${type}, placeholder=${placeholder}`);
+      }
+    }
+    
+  } catch (error) {
+    console.error('Error:', error.message);
+  } finally {
+    await page.waitForTimeout(5000);
+    await browser.close();
+  }
+})();