cv-c3c: add --image flag to deployment restart command

Allows callers to override container images during restart, e.g.:
  laconic-so deployment restart --image backend=ghcr.io/org/app:sha123

The override is applied to the k8s Deployment spec before
create-or-patch. Docker/compose deployers accept the parameter
but ignore it.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

stack_orchestrator/deploy/deployer.py

@@ -20,7 +20,7 @@ from typing import Optional
 
 class Deployer(ABC):
     @abstractmethod
-    def up(self, detach, skip_cluster_management, services):
+    def up(self, detach, skip_cluster_management, services, image_overrides=None):
         pass
 
     @abstractmethod