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/theme/ThemeContext.tsx

@@ -0,0 +1,74 @@
+import React, { PropsWithChildren, useEffect, useState } from 'react';
+import { useColorScheme } from 'react-native';
+import { colors } from './colors';
+import { spacing } from './spacing';
+import { typography } from './typography';
+
+export type ThemeMode = 'light' | 'dark' | 'system';
+
+export type ThemeContextValue = {
+  colors: typeof colors;
+  typography: typeof typography;
+  spacing: typeof spacing;
+  isDark: boolean;
+};
+
+const fallbackThemeValue: ThemeContextValue = {
+  colors,
+  typography,
+  spacing,
+  isDark: true,
+};
+
+export const ThemeContext = React.createContext<ThemeContextValue>(fallbackThemeValue);
+
+const isValidThemeMode = (value: unknown): value is ThemeMode => {
+  return value === 'light' || value === 'dark' || value === 'system';
+};
+
+const readThemeFromSettings = async (): Promise<ThemeMode> => {
+  try {
+    const settingsStore = (await import('../stores/settingsStore')) as Record<string, unknown>;
+    const stateAccessors = [settingsStore.useSettingsStore, (settingsStore as { useStore?: unknown }).useStore].filter(
+      (candidate): candidate is { getState: () => { theme?: unknown } } =>
+        typeof candidate === 'function' &&
+        typeof (candidate as { getState?: unknown }).getState === 'function',
+    );
+
+    for (const accessor of stateAccessors) {
+      const state = accessor.getState?.() as { theme?: unknown } | undefined;
+      const candidateTheme = state?.theme;
+      if (isValidThemeMode(candidateTheme)) {
+        return candidateTheme;
+      }
+    }
+  } catch {
+    // No-op if store is unavailable during bootstrap.
+  }
+
+  return 'system';
+};
+
+export const ThemeProvider = ({ children }: PropsWithChildren<object>) => {
+  const [themeMode, setThemeMode] = useState<ThemeMode>('system');
+  const systemScheme = useColorScheme() ?? 'light';
+
+  useEffect(() => {
+    void readThemeFromSettings().then(setThemeMode);
+  }, []);
+
+  const isDark = themeMode === 'dark' || (themeMode === 'system' && systemScheme === 'dark');
+
+  return (
+    <ThemeContext.Provider
+      value={{
+        colors,
+        typography,
+        spacing,
+        isDark,
+      }}
+    >
+      {children}
+    </ThemeContext.Provider>
+  );
+};