fix: pass EMBED_API_KEY to container in docker-compose

Required for HuggingFace TEI embedding provider. Defaults to empty
string so existing deployments using Gemini embeddings are unaffected.

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

Author: Alexey Panfilov

docker-compose.yml

@@ -10,6 +10,7 @@ services:
       - DEEPSEEK_API_KEY=${DEEPSEEK_API_KEY}
       - GEMINI_API_KEY=${GEMINI_API_KEY}
       - QWEN_API_KEY=${QWEN_API_KEY:-}
+      - EMBED_API_KEY=${EMBED_API_KEY:-}
       - TZ=${TZ:-Europe/Belgrade}
     volumes:
       - ./data:/app/data