Demote per-chunk CP per-layer transfer register log to debug

'[CP_PER_LAYER_TRANSFER] registered room=... chunk=...' fired at INFO
once per room per chunk on every prefill send. The one-time manager
registration stays INFO and failure paths stay WARNING; the
success-side finish log was already debug.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

python/sglang/srt/disaggregation/mooncake/conn.py

@@ -455,7 +455,7 @@ class MooncakeKVManager(CommonKVManager):
         if ctx is None:
             return False
         mgr.register(room, ctx, chunk_key=chunk_key)
-        logger.info(
+        logger.debug(
             "[CP_PER_LAYER_TRANSFER] registered room=%s chunk=%s owned_pages=%d",
             room,
             chunk_key,