FIX: Correct Keycloak callback path to /api

##  **Fixed 404 Error:**

### **Issue:**
- Keycloak was redirecting to /auth/keycloak/callback
- But our server endpoint was at /api/auth/keycloak/callback
- This caused a 404 Page Not Found error

### **Solution:**
-  Updated useCustomAuth.ts redirect URI to include /api prefix
-  Updated server callback endpoint to match the new path
-  Both client and server now use: /api/auth/keycloak/callback

### **Files Changed:**
- composables/useCustomAuth.ts - Updated login redirect URI
- server/api/auth/keycloak/callback.ts - Updated token exchange redirect URI

##  **Result:**
Now when users click 'Login with SSO':
1. Redirect to Keycloak
2. Keycloak redirects back to /api/auth/keycloak/callback
3. Server handles the callback properly
4. User gets authenticated and redirected to dashboard

The 404 error should be resolved and SSO login should work!

composables/useCustomAuth.ts

@@ -36,7 +36,7 @@ export const useCustomAuth = () => {
     const authUrl = 'https://auth.portnimara.dev/realms/client-portal/protocol/openid-connect/auth?' + 
       new URLSearchParams({
         client_id: 'client-portal',
-        redirect_uri: 'https://client.portnimara.dev/auth/keycloak/callback',
+        redirect_uri: 'https://client.portnimara.dev/api/auth/keycloak/callback',
         response_type: 'code',
         scope: 'openid profile email',
         state: Math.random().toString(36).substring(2)

server/api/auth/keycloak/callback.ts

@@ -32,7 +32,7 @@ export default defineEventHandler(async (event) => {
         client_id: 'client-portal',
         client_secret: process.env.KEYCLOAK_CLIENT_SECRET || '',
         code: code as string,
-        redirect_uri: 'https://client.portnimara.dev/auth/keycloak/callback'
+        redirect_uri: 'https://client.portnimara.dev/api/auth/keycloak/callback'
       }).toString()
     }) as any