Use individual credentials for azure/login in deploy workflow

Replace AZURE_CREDENTIALS JSON blob with client-id, tenant-id,
subscription-id fields. Reuses ACR_CLIENT_ID from docker workflow.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: johnmathews

.github/workflows/deploy.yml

@@ -23,7 +23,10 @@ jobs:
       - name: Log in to Azure
         uses: azure/login@v2
         with:
-          creds: ${{ secrets.AZURE_CREDENTIALS }}
+          client-id: ${{ secrets.ACR_CLIENT_ID }}
+          tenant-id: ${{ secrets.AZURE_TENANT_ID }}
+          subscription-id: ${{ secrets.AZURE_SUBSCRIPTION_ID }}
+          enable-AzPSSession: false
 
       - name: Set AKS context
         run: |