chore: add platforms to welcome titles

[Meng-Heng]

fixes: #12896.

This PR is ready for reviews.

@keymanapp-test-bot skip

[keymanapp-test-bot]

User Test Results

Test specification and instructions

User tests are not required

Test Artifacts

• Android
  • Keyman for Android apk
  • FirstVoices for Android 16.0 apk
  • FirstVoices Keyboards for Android apk
  • KeyboardHarness apk
  • Keyman for Android 16.0 apk
  • KMSample1 apk
  • KMSample2 apk
• iOS
  • Keyman for iOS (simulator image)
  • FirstVoices Keyboards for iOS (simulator image)
  • TestFlight internal PR build version - 18.0.175 (0.12990.12659)
• Linux
  • Keyman for Linux: focal
  • Keyman for Linux: jammy
  • Keyman for Linux: noble
  • Keyman for Linux: oracular
  • Keyman for Linux: plucky
• macOS
  • Keyman for macOS
• Windows
  • Keyman for Windows
  • FirstVoices Keyboards for Windows
  • Text Editor (32 bit)
  • Text Editor (64 bit)

[mcdurdin]

@Meng-Heng, I updated your PR to say "chore: add platforms to welcome titles" instead of "chore: adds platforms to welcome titles".

When writing PR titles (and commit messages), please refer to https://github.com/keymanapp/keyman/wiki/Pull-Request-and-Commit-workflow-notes#commit for guidelines, particularly:

• Use the present tense ("add feature" not "added feature")
• Use the imperative mood ("move cursor to..." not "moves cursor to...", nor "cursor movement", nor "cursor now moves")

(I know that these things are really tricky to get right in English!)