feat: move all remaining inline logic from routers to services (Tier 2)

backend/app/routers/campaigns.py

@@ -30,7 +30,7 @@ from app.services.campaign_crud_service import (
     serialize_campaign,
     update_campaign as crud_update,
 )
-from app.services.notification_service import create_notification
+from app.services.notification_service import notify_role
 from app.services.audit_service import log_action
 
 logger = logging.getLogger(__name__)
@@ -237,17 +237,15 @@ def activate_campaign(
     db.commit()
     db.refresh(campaign)
 
-    red_techs = db.query(User).filter(User.role == "red_tech", User.is_active == True).all()  # noqa: E712
-    for user in red_techs:
-        create_notification(
-            db,
-            user_id=user.id,
-            type="campaign_activated",
-            title="Campaign activated",
-            message=f'Campaign "{campaign.name}" has been activated.',
-            entity_type="campaign",
-            entity_id=campaign.id,
-        )
+    notify_role(
+        db,
+        role="red_tech",
+        type="campaign_activated",
+        title="Campaign activated",
+        message=f'Campaign "{campaign.name}" has been activated.',
+        entity_type="campaign",
+        entity_id=campaign.id,
+    )
 
     log_action(
         db,