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/hooks/useServerReachability.ts

@@ -0,0 +1,52 @@
+import { useEffect, useState } from 'react';
+import { apiService } from '@/services/api.service';
+
+interface ServerReachability {
+  reachable: boolean;
+  latencyMs: number | null;
+}
+
+const POLL_MS = 10000;
+
+export function useServerReachability(): ServerReachability {
+  const [state, setState] = useState<ServerReachability>({
+    reachable: false,
+    latencyMs: null,
+  });
+
+  useEffect(() => {
+    let active = true;
+
+    const check = async () => {
+      const started = Date.now();
+      try {
+        await apiService.getStatus();
+        if (!active) {
+          return;
+        }
+        setState({
+          reachable: true,
+          latencyMs: Date.now() - started,
+        });
+      } catch {
+        if (!active) {
+          return;
+        }
+        setState({
+          reachable: false,
+          latencyMs: null,
+        });
+      }
+    };
+
+    void check();
+    const timer = setInterval(check, POLL_MS);
+
+    return () => {
+      active = false;
+      clearInterval(timer);
+    };
+  }, []);
+
+  return state;
+}