feat: Implement RSSI service for iOS and Web platforms

- Added IosRssiService to handle synthetic RSSI data for iOS.
- Created WebRssiService to simulate RSSI scanning on the web.
- Defined shared types for WifiNetwork and RssiService in rssi.service.ts.
- Introduced simulation service to generate synthetic sensing data.
- Implemented WebSocket service for real-time data handling with reconnection logic.
- Established Zustand stores for managing application state related to MAT and pose data.
- Developed theme context and utility functions for consistent styling and formatting.
- Added type definitions for various application entities including API responses and sensing data.
- Created utility functions for color mapping and URL validation.
- Configured TypeScript settings for the mobile application.

ui/mobile/src/services/rssi.service.web.ts

@@ -0,0 +1,46 @@
+import type { RssiService, WifiNetwork } from './rssi.service';
+
+class WebRssiService implements RssiService {
+  private timer: ReturnType<typeof setInterval> | null = null;
+  private listeners = new Set<(networks: WifiNetwork[]) => void>();
+
+  startScanning(intervalMs: number): void {
+    console.warn('Web RSSI scanning not available; returning synthetic network data.');
+    this.stopScanning();
+    this.timer = setInterval(() => {
+      this.broadcast([
+        { ssid: 'WiFi-DensePose', bssid: 'AA:BB:CC:DD:EE:01', level: -55 },
+        { ssid: 'WiFi-Guest', bssid: 'AA:BB:CC:DD:EE:02', level: -72 },
+      ]);
+    }, intervalMs);
+    this.broadcast([
+      { ssid: 'WiFi-DensePose', bssid: 'AA:BB:CC:DD:EE:01', level: -55 },
+    ]);
+  }
+
+  stopScanning(): void {
+    if (this.timer) {
+      clearInterval(this.timer);
+      this.timer = null;
+    }
+  }
+
+  subscribe(listener: (networks: WifiNetwork[]) => void): () => void {
+    this.listeners.add(listener);
+    return () => {
+      this.listeners.delete(listener);
+    };
+  }
+
+  private broadcast(networks: WifiNetwork[]): void {
+    this.listeners.forEach((listener) => {
+      try {
+        listener(networks);
+      } catch {
+        // listener safety
+      }
+    });
+  }
+}
+
+export const rssiService = new WebRssiService();