feat: add DeepSeek and NVIDIA NIM providers

- Add deepseek and nvidia entries to gateway-provider config

- Add DEEPSEEK_API_KEY and NVIDIA_API_KEY to .env.example

- Add deepseek and nvidia to doctor's LLM provider check

- Fix remaining harness-log → log-message reference

infrastructure/docker/docker-compose.yml

@@ -1,9 +1,9 @@
 services:
-  opencortex:
+  passepartout:
     build:
       context: ../../
       dockerfile: infrastructure/docker/Dockerfile
-    container_name: opencortex
+    container_name: passepartout
     env_file: ../../.env
     volumes:
       - ../../../..:/memex