iOS push notification setup for client_app and mitra_app

- Add Runner.entitlements with aps-environment capability
- Add UIBackgroundModes (remote-notification, fetch) to Info.plist
- Add CODE_SIGN_ENTITLEMENTS to Debug/Release/Profile build configs
- Add GoogleService-Info.plist for both apps
- Upgrade Firebase packages and web_socket_channel to fix CocoaPods conflict
- Set client_app Podfile iOS platform to 15.0
- Fix mitra_app Xcode bundle ID to match Firebase (com.halobestie.mitra)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client_app/ios/Podfile

@@ -0,0 +1,42 @@
+platform :ios, '15.0'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def flutter_root
+  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'Generated.xcconfig'), __FILE__)
+  unless File.exist?(generated_xcode_build_settings_path)
+    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure flutter pub get is executed first"
+  end
+
+  File.foreach(generated_xcode_build_settings_path) do |line|
+    matches = line.match(/FLUTTER_ROOT\=(.*)/)
+    return matches[1].strip if matches
+  end
+  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Generated.xcconfig, then run flutter pub get"
+end
+
+require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
+
+flutter_ios_podfile_setup
+
+target 'Runner' do
+  use_frameworks!
+
+  flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
+  target 'RunnerTests' do
+    inherit! :search_paths
+  end
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    flutter_additional_ios_build_settings(target)
+  end
+end