refactor: remove internal/domain package, move types to correct packages

- ImageID + ContainerID → internal/docker/types.go
- UnparsedURL → internal/service/webhook/types.go
- Delete internal/domain/ entirely
- Update all imports throughout the codebase

internal/service/deploy/deploy_container_test.go

@@ -7,7 +7,7 @@ import (
 	"testing"
 
 	"git.eeqj.de/sneak/upaas/internal/database"
-	"git.eeqj.de/sneak/upaas/internal/domain"
+	"git.eeqj.de/sneak/upaas/internal/docker"
 	"git.eeqj.de/sneak/upaas/internal/models"
 	"git.eeqj.de/sneak/upaas/internal/service/deploy"
 )
@@ -28,7 +28,7 @@ func TestBuildContainerOptionsUsesImageID(t *testing.T) {
 	log := slog.New(slog.NewTextHandler(os.Stderr, nil))
 	svc := deploy.NewTestService(log)
 
-	const expectedImageID = domain.ImageID("sha256:abc123def456")
+	const expectedImageID = docker.ImageID("sha256:abc123def456")
 
 	opts, err := svc.BuildContainerOptionsExported(context.Background(), app, expectedImageID)
 	if err != nil {