[Feat] File integrity check for downloaded models

[a-ghorbani]

Description

Added a file integrity verification check for downloaded models to ensure file consistency and help users identify corrupted downloads as opposed to model loading fails.

• Added checkModelFileIntegrity utility that:
  • Compares local file hash with HuggingFace's LFS hash (lfs.oid)
  • Fetches missing file details from HF when needed (for backward compatibility)
  • Compares actual file size on disk with expected size for display only
• Added visual warning when integrity check fails

Platform Affected

• iOS
• Android

Checklist

• Necessary comments have been made.
• I have tested this change on:
  • iOS Simulator/Device
  • Android Emulator/Device
• Unit tests and integration tests pass locally.