fix(ci): remove duplicate provenance keys causing YAML parse error

Duplicate 'provenance: false' in each docker/build-push-action step caused
Gitea to reject the workflow file, breaking push CI and workflow_dispatch.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.gitea/workflows/ci.yml

@@ -96,7 +96,6 @@ jobs:
           file: Dockerfile
           target: runner
           push: true
-          provenance: false
           tags: |
             git.farh.net/groombook/api:${{ steps.version.outputs.tag }}
             ${{ github.ref == 'refs/heads/main' && 'git.farh.net/groombook/api:latest' || '' }}
@@ -111,7 +110,6 @@ jobs:
           file: Dockerfile
           target: migrate
           push: true
-          provenance: false
           tags: |
             git.farh.net/groombook/migrate:${{ steps.version.outputs.tag }}
             ${{ github.ref == 'refs/heads/main' && 'git.farh.net/groombook/migrate:latest' || '' }}
@@ -126,7 +124,6 @@ jobs:
           file: Dockerfile
           target: seed
           push: true
-          provenance: false
           tags: |
             git.farh.net/groombook/seed:${{ steps.version.outputs.tag }}
             ${{ github.ref == 'refs/heads/main' && 'git.farh.net/groombook/seed:latest' || '' }}
@@ -141,7 +138,6 @@ jobs:
           file: Dockerfile
           target: reset
           push: true
-          provenance: false
           tags: |
             git.farh.net/groombook/reset:${{ steps.version.outputs.tag }}
             ${{ github.ref == 'refs/heads/main' && 'git.farh.net/groombook/reset:latest' || '' }}