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.

bot/src/stream/novnc.ts

@@ -3,7 +3,8 @@
  *
  * Does not broadcast natively into Discord. Instead it shares a noVNC web URL
  * that anyone can open in a browser to watch (and optionally control) the VNC
- * desktop live. Set NOVNC_URL in .env (e.g. http://192.168.10.9:6080/vnc.html).
+ * desktop live. Set NOVNC_URL in .env to the browser host's LAN IP
+ * (e.g. http://<browser-host-ip>:6080/vnc.html).
  *
  * Stand up noVNC once on the host with websockify, e.g.:
  *   websockify --web=/usr/share/novnc 6080 localhost:5901
@@ -22,7 +23,7 @@ export class NoVncStreamer implements ScreenStreamer {
 
   async start(_ctx: StreamContext): Promise<string> {
     if (!this.config.novncUrl) {
-      return "NOVNC_URL이 설정되지 않았습니다 (.env). 예: http://192.168.10.9:6080/vnc.html";
+      return "NOVNC_URL이 설정되지 않았습니다 (.env). 예: http://<브라우저호스트IP>:6080/vnc.html";
     }
     this.active = true;
     return `🖥️ VNC 화면 실시간 보기 (브라우저): ${this.config.novncUrl}`;