refactor(proxy): move proxy logic to services.mitmproxy and update Docker service model

- Rename DockerService to DockerContainer and add folder attribute
- Move proxy-related modules (models, validator) to services.mitmproxy
- Update imports and references to new module locations
- Refactor Docker utilities to use DockerContainer and improve service discovery
- Add manager.py with create_proxy utility stub
- Initialize discovered Docker services at app startup and warn if none found

app/integrations/docker/__init__.py

@@ -2,15 +2,13 @@ from integrations.docker.compose import (
 	find_docker_compose,
 	get_all_services,
 	get_services,
-	get_visible_folders,
 )
 from integrations.docker.editor import change_port
-from integrations.docker.models import DockerService
+from integrations.docker.models import DockerContainer
 
 __all__ = [
-	"DockerService",
+	"DockerContainer",
 	"find_docker_compose",
-	"get_visible_folders",
 	"get_services",
 	"get_all_services",
 	"change_port",