ci(deploy): Add 'newt' deploy option and make stack selection explicit

The `newt` stack has been added to the list of available deployment options for the Gitea Actions workflow.
Additionally, the default value for the `stack` input has been removed, making it a mandatory selection. This ensures that users explicitly choose which service to deploy, preventing unintended deployments and improving clarity.

.gitea/workflows/deploy.yaml

@@ -8,13 +8,13 @@ on:
         description: 'Stack to deploy'
         required: true
         # Default can be anything, or leave empty
-        default: 'ai-backend' 
+        default: 
         type: choice
         options:
           # Just list the filenames (without .nomad)
           - ai-backend
           - ai-frontend
-          # - uptime-kuma (Add this later)
+          - newt
 
 jobs:
   deploy: