Refactor: Remove background task management and related hooks

- Deleted `useBackgroundTasks.ts` hook and its associated logic for managing background tasks.
- Removed `backgroundTaskManager.ts` service and all related task definitions and registrations.
- Cleaned up `Podfile.lock` and `package.json` to remove unused dependencies related to background tasks.
- Updated iOS project files to eliminate references to removed background task components.
- Added new background fetch identifier in `Info.plist` for future use.

android/settings.gradle

@@ -1,39 +0,0 @@
-pluginManagement {
-  def reactNativeGradlePlugin = new File(
-    providers.exec {
-      workingDir(rootDir)
-      commandLine("node", "--print", "require.resolve('@react-native/gradle-plugin/package.json', { paths: [require.resolve('react-native/package.json')] })")
-    }.standardOutput.asText.get().trim()
-  ).getParentFile().absolutePath
-  includeBuild(reactNativeGradlePlugin)
-  
-  def expoPluginsPath = new File(
-    providers.exec {
-      workingDir(rootDir)
-      commandLine("node", "--print", "require.resolve('expo-modules-autolinking/package.json', { paths: [require.resolve('expo/package.json')] })")
-    }.standardOutput.asText.get().trim(),
-    "../android/expo-gradle-plugin"
-  ).absolutePath
-  includeBuild(expoPluginsPath)
-}
-
-plugins {
-  id("com.facebook.react.settings")
-  id("expo-autolinking-settings")
-}
-
-extensions.configure(com.facebook.react.ReactSettingsExtension) { ex ->
-  if (System.getenv('EXPO_USE_COMMUNITY_AUTOLINKING') == '1') {
-    ex.autolinkLibrariesFromCommand()
-  } else {
-    ex.autolinkLibrariesFromCommand(expoAutolinking.rnConfigCommand)
-  }
-}
-expoAutolinking.useExpoModules()
-
-rootProject.name = 'digital-pilates'
-
-expoAutolinking.useExpoVersionCatalog()
-
-include ':app'
-includeBuild(expoAutolinking.reactNativeGradlePlugin)