feat: add build-and-push and ssh-deploy composite actions with image tagging support

build-and-push/action.yaml

@@ -17,7 +17,7 @@ inputs:
     description: Full image reference (host/path/name) without tag
     required: true
   image_tag:
-    description: Tag to apply to the built image
+    description: Tag(s) to apply to the built image. Comma-separated for multiple tags (e.g. "latest,abc1234").
     required: false
     default: latest
   platforms:
@@ -90,4 +90,4 @@ runs:
         builder: remote-builder
         platforms: ${{ inputs.platforms }}
         tags: |
-          ${{ inputs.image }}:${{ inputs.image_tag }}
+          ${{ join(fromJSON(format('["{0}:{1}"]', inputs.image, join(split(inputs.image_tag, ','), format('","{0}:', inputs.image)))), '\n') }}