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.
The Portainer redeploy endpoint POST /api/deploy/{stackId} requires
POST requests. wget defaults to GET, so --method=POST is needed.
Applied to both Dev (test_image_build_push.yml) and Prod
(prod_image_tag_promote.yaml) workflow files.
