fix(config): use docker hostnames for tatlock and searxng defaults

The homelab is retiring *.schweitz.internal and will rebind host ports
to 127.0.0.1, so container-to-container traffic must use container
names on the docker-dataplane network. Switch defaults from host
IP:port to http://tatlock:8000 and http://searxng:8080 (SearXNG's
internal port is 8080; 8087 is only the host-published port).

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

webber-api/.env.example

@@ -18,9 +18,12 @@ OLLAMA_AGENT_MODEL=mistral-nemo-large:latest
 OLLAMA_EMBED_MODEL=nomic-embed-text:latest
 
 # Auth - Tatlock integration (optional)
-# TATLOCK_API_URL=http://192.168.86.149:8000
+# TATLOCK_API_URL=http://tatlock:8000
 # INTERNAL_API_KEY=your-internal-key
 
+# Web search - SearXNG (container name on docker-dataplane; internal port 8080)
+# SEARXNG_URL=http://searxng:8080
+
 # Tool execution
 TOOL_TIMEOUT_SECONDS=120
 SANDBOX_ENABLED=true