feat(compose): allow external Ollama via OLLAMA_BASE_URL override

For the split where the LLM runs on a separate LAN host (e.g. a GPU box at
192.168.10.9) and the app stack runs elsewhere (192.168.10.5), the brain must
reach Ollama over the network. The javis service hardcoded
OLLAMA_BASE_URL=http://ollama:11434, ignoring any .env value, so the app could
only use the in-stack Ollama. Make it ${OLLAMA_BASE_URL:-http://ollama:11434}:
default unchanged (all-in-one), overridable to point at an external Ollama.
Document the external-Ollama setup in .env.example and DEPLOY.md, refresh the
browser-host IP examples (.9→.5), and de-hardcode the .9 example in novnc.ts.

.env.example

@@ -51,7 +51,13 @@ MELO_FALLBACK_PIPER=0
 # Jarvis brain (Ollama-backed). In Docker these populate the rendered
 # config (docker/jarvis-config.template.json). See src/jarvis/config.py.
 # ---------------------------------------------------------------------------
-# In docker-compose this is overridden to http://ollama:11434 automatically.
+# In docker-compose this defaults to the in-stack `ollama` service
+# (http://ollama:11434). To use an EXTERNAL Ollama on another LAN machine (e.g. a
+# GPU host), set it here to that host's IP — the compose now respects this value:
+#   OLLAMA_BASE_URL=http://192.168.10.9:11434   # Ollama runs on the .9 host
+# In that split setup: do NOT start the in-stack ollama/ollama-init (run
+# `docker compose up -d javis`), pull the models on the LLM host, and make that
+# host's Ollama listen on the LAN (OLLAMA_HOST=0.0.0.0:11434).
 OLLAMA_BASE_URL=http://127.0.0.1:11434
 # qwen2.5:3b — small non-reasoning instruct model. ~2.4GB, runs 100% on the GPU
 # (the 8B offloads ~8% to CPU), warm voice turns ~2-4s vs ~5-7s on 8B. Clean