fix(ocr): reduce mem_limit to 4g, allow 4g swap for 16GB dev machines

mem_limit 4g keeps more RAM free for the host. memswap_limit 8g
(= 4g swap) lets peaks spill to disk instead of OOM-killing.
Slower during peak inference but won't starve the dev machine.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -78,8 +78,8 @@ services:
       dockerfile: Dockerfile
     container_name: archive-ocr
     restart: unless-stopped
-    mem_limit: 6g
-    memswap_limit: 6g
+    mem_limit: 4g
+    memswap_limit: 8g
     volumes:
       - ocr_models:/app/models
     environment: