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.

ios/digitalpilates.xcodeproj/project.pbxproj

@@ -268,7 +268,6 @@
 				"${PODS_CONFIGURATION_BUILD_DIR}/EXConstants/EXConstants.bundle",
 				"${PODS_CONFIGURATION_BUILD_DIR}/EXConstants/ExpoConstants_privacy.bundle",
 				"${PODS_CONFIGURATION_BUILD_DIR}/EXNotifications/ExpoNotifications_privacy.bundle",
-				"${PODS_CONFIGURATION_BUILD_DIR}/EXTaskManager/ExpoTaskManager_privacy.bundle",
 				"${PODS_CONFIGURATION_BUILD_DIR}/ExpoFileSystem/ExpoFileSystem_privacy.bundle",
 				"${PODS_CONFIGURATION_BUILD_DIR}/ExpoSystemUI/ExpoSystemUI_privacy.bundle",
 				"${PODS_CONFIGURATION_BUILD_DIR}/PurchasesHybridCommon/PurchasesHybridCommon.bundle",
@@ -293,7 +292,6 @@
 				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/EXConstants.bundle",
 				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/ExpoConstants_privacy.bundle",
 				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/ExpoNotifications_privacy.bundle",
-				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/ExpoTaskManager_privacy.bundle",
 				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/ExpoFileSystem_privacy.bundle",
 				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/ExpoSystemUI_privacy.bundle",
 				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/PurchasesHybridCommon.bundle",