fix(ci): explicitly use shell: bash for all steps

.gitea/workflows/deploy.yml

@@ -29,6 +29,7 @@ jobs:
       project_name:     ${{ steps.determine.outputs.project_name }}
     steps:
       - name: 🔍 Debug Info
+        shell: bash
         run: |
           echo "ref_name: ${{ github.ref_name }}"
           echo "ref_type: ${{ github.ref_type }}"
@@ -36,6 +37,7 @@ jobs:
 
       - name: 🧹 Maintenance (Runner Cleanup)
         continue-on-error: true
+        shell: bash
         run: |
           docker image prune -f || true
           docker builder prune -f --filter "until=24h" || true
@@ -47,6 +49,7 @@ jobs:
 
       - name: 🔍 Determine Environment
         id: determine
+        shell: bash
         run: |
           TAG="${{ github.ref_name }}"
           SHORT_SHA=$(echo "${{ github.sha }}" | cut -c1-7)
@@ -125,6 +128,7 @@ jobs:
         run: echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login registry.infra.mintel.me -u "${{ secrets.REGISTRY_USERNAME }}" --password-stdin
       
       - name: 🏗️ Build and Push
+        shell: bash
         run: |
           docker buildx build \
             --pull \
@@ -189,6 +193,7 @@ jobs:
       image: catthehacker/ubuntu:act-latest
     steps:
       - name: Notify Gotify
+        shell: bash
         run: |
           STATUS="${{ needs.deploy.result }}"
           COLOR="info"