Deploy chat_web_app via server-infra (node-static) (#15)

## Summary

Implements [chat_web_app#13](#13) Part A: wire the CRA frontend into the same **node-static** deploy path as `dta_webapp` (no Docker for serving).

- `build:prod` / `build:beta` write into `/var/www/{env}.chat.aimloperations/html`
- API/WS URLs come from `REACT_APP_*` (`.env.production` / `.env.beta`) instead of hardcoded localhost
- Gitea unit tests + auto deploy-prod on `master`; deploy-beta via `workflow_dispatch`
- README documents local dev, env files, and webroot layout

Branch includes the #11 unit-test commit (`test:ci`) so CI has a green suite.

Companion server-infra branch (Part B): `issue-13-register-chat-web-app` on `ai_ml_operations/server-infra`.

## Test plan

- [ ] `cd llm-fe && npm run test:ci`
- [ ] Merge + ensure Unit Tests workflow passes on PR
- [ ] Merge server-infra `issue-13-register-chat-web-app`, then sync/pull on runner
- [ ] Redeploy web-static (or full host provision) so nginx listens on **8082**
- [ ] Manual: `server-infra/scripts/deploy.sh --app chat_web_app --env prod --ref <sha>`
- [ ] NPM: point `chat.aimloperations.com` at `adama:8082` + `roslin:8082` + `ai-server-4080:8082`
- [ ] Confirm built assets hit `https://chatbackend.aimloperations.com`Reviewed-on: #15

llm-fe/src/axiosApi.js

@@ -1,9 +1,7 @@
 import axios from "axios";
 const Cookies = require("js-cookie");
 
-const baseURL = "http://localhost:8011/api/";
-//const baseURL = 'https://chatbackend.aimloperations.com/api/';
-//const baseURL = process.env.REACT_APP_BACKEND_REST_API_BASE_URL;
+const baseURL = process.env.REACT_APP_BACKEND_REST_API_BASE_URL;
 
 export const axiosInstance = axios.create({
   baseURL: baseURL,

llm-fe/src/llm-fe/contexts/WebSocketContext.js

@@ -70,11 +70,7 @@ function WebSocketProvider({ children }) {
   useEffect(() => {
     /* WS initialization and cleanup */
     if (account) {
-      ws.current = new WebSocket(`ws://localhost:8011/ws/chat_again/`);
-      //ws.current = new WebSocket(`ws://localhost:8011/ws/conditional_chat/`);
-      //ws.current = new WebSocket('wss://chatbackend.aimloperations.com/ws/chat_again/')
-      //ws.current = new WebSocket('wss://chatbackend.aimloperations.com/ws/conditional_chat/')
-      //ws.current = process.env.REACT_APP_BACKEND_WS_API_BASE_URL;
+      ws.current = new WebSocket(process.env.REACT_APP_BACKEND_WS_API_BASE_URL);
 
       ws.current.onopen = () => {
         setSocket(ws.current);