feat: send logs to UI

Added SSE endpoint `/logs/stream` for the UI to listen to logs.

ref: N25B-242

.logging_config.yaml

@@ -15,7 +15,7 @@ formatters:
   # User-facing UI (structured JSON)
   json_experiment:
     (): "pythonjsonlogger.jsonlogger.JsonFormatter"
-    format: "{asctime} {name} {levelname} {message}"
+    format: "{name} {levelname} {levelno} {message} {created} {relativeCreated}"
     style: "{"
 
 handlers:
@@ -28,7 +28,6 @@ handlers:
     class: zmq.log.handlers.PUBHandler
     level: DEBUG
     formatter: json_experiment
-    interface_or_socket: "PLACEHOLDER"
 
 # Level of external libraries
 root:
@@ -37,5 +36,5 @@ root:
 
 loggers:
   control_backend:
-    level: INFO
+    level: DEBUG
     handlers: [ui]