fix(music): add lavasrc-patcher sidecar for auto-applying runtime config

LavaSrc plugin config (preferPartnerApi, customTokenEndpoint, spDc)
doesn't bind from YAML in Lavalink 4. Added a one-shot sidecar container
that applies the config via PATCH endpoint after Lavalink becomes healthy.
Also cleaned up DEBUG logging.

docker-compose.yml

@@ -31,6 +31,16 @@ services:
       retries: 3
       start_period: 20s
 
+  lavasrc-patcher:
+    build:
+      context: ./lavalink
+      dockerfile: Dockerfile.config-patcher
+    container_name: lavasrc-patcher
+    depends_on:
+      lavalink:
+        condition: service_healthy
+    restart: "no"
+
   bot:
     build: .
     container_name: loki-bot