Hithomelabs/CFTunnels#139: Simplify workflow_dispatch input type for Gitea compatibility

Remove 'type: choice' and 'options:' from workflow_dispatch inputs,
replacing with 'type: string'. The Gitea Actions runner may not support
the 'choice' type with 'options' subfield, causing the entire workflow
to fail registration silently. The workflow already has runtime
validation (lines 40-44) that rejects invalid environment values, so
the 'choice' type was redundant.

.gitea/workflows/portainer_automation_build_push.yml

@@ -9,13 +9,10 @@ on:
   workflow_dispatch:
     inputs:
       environment:
-        description: 'Target environment (test → PATCH bump, prod → MINOR bump)'
+        description: 'Target environment: "test" (PATCH bump) or "prod" (MINOR bump). Invalid values fail early with validation error.'
         required: true
         default: 'test'
-        type: choice
+        type: string
-        options:
-          - test
-          - prod
 
 jobs:
   version: