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/services/mitmproxy/manager.py

@@ -0,0 +1,27 @@
+import uuid
+from pathlib import Path
+
+from integrations.docker import DockerContainer
+from services.mitmproxy.models import ServiceConfig
+
+
+async def create_proxy(
+        port: int,
+        name: str,
+        service: ServiceConfig,
+        code: str,
+        services: list[DockerContainer]
+) -> int:
+    """
+    Utility function that will:
+     - run ``integrations/docker`` utilities to change the old port of original service to a random one
+     - write ``code`` into ``/tmp/theplug/{random}.py``
+     - start a subprocess via asyncio
+     - return the proxy infos (pid, )
+    """
+    path = Path("/tmp/theplug/{random}.py".format(random=str(uuid.uuid4())))
+    path.parent.mkdir(parents=True, exist_ok=True)
+
+    path.write_text(code, encoding="utf-8")
+
+    return 0