fix(ci): use single label runs-on for Forgejo runner v12 compatibility

Runner v12.7.3 uses labels: [docker linux debian ubuntu-latest].
Changed from 'runs-on: [linux, docker]' to 'runs-on: docker' to fix:
- 'runs-on key not defined' error
- 'github.ref == refs/heads/main evaluated to false' error

.forgejo/workflows/deploy.yaml

@@ -11,7 +11,7 @@ env:
 
 jobs:
   lint:
-    runs-on: [linux, docker]
+    runs-on: docker
     container:
       image: catthehacker/ubuntu:act-latest
     steps:
@@ -30,7 +30,7 @@ jobs:
         run: black --check app tests scripts
 
   test:
-    runs-on: [linux, docker]
+    runs-on: docker
     container:
       image: catthehacker/ubuntu:act-latest
     env:
@@ -61,7 +61,7 @@ jobs:
             -v --tb=short
 
   type-check:
-    runs-on: [linux, docker]
+    runs-on: docker
     container:
       image: catthehacker/ubuntu:act-latest
     steps:
@@ -86,7 +86,7 @@ jobs:
           echo "Type check completed successfully"
 
   build:
-    runs-on: [linux, docker]
+    runs-on: docker
     needs: [lint, test]
     container:
       image: catthehacker/ubuntu:act-latest
@@ -120,7 +120,7 @@ jobs:
           provenance: false
 
   deploy:
-    runs-on: [linux, docker]
+    runs-on: docker
     needs: build
     if: github.ref == 'refs/heads/main'
     container: