docs: Revamp README and UI documentation; enhance CLI usage instructions and API configuration details

ui/config/api.config.js

@@ -1,7 +1,7 @@
 // API Configuration for WiFi-DensePose UI
 
 export const API_CONFIG = {
-  BASE_URL: window.location.origin,
+  BASE_URL: 'http://localhost:8000',  // FastAPI backend port
   API_VERSION: '/api/v1',
   WS_PREFIX: 'ws://',
   WSS_PREFIX: 'wss://',
@@ -105,7 +105,8 @@ export function buildWsUrl(endpoint, params = {}) {
     ? API_CONFIG.WSS_PREFIX 
     : API_CONFIG.WS_PREFIX;
   
-  const host = window.location.host;
+  // Use localhost:8000 for WebSocket connections to match FastAPI backend
+  const host = 'localhost:8000';
   let url = `${protocol}${host}${endpoint}`;
   
   // Add query parameters