fix(ios): prevent crash when printing images without internet connection

[tolypash]

Description

Fix crash when printing images without internet connection on iOS.

Problem

The app crashes with UIGraphicsBeginImageContext() failed to allocate CGBitampContext: size={472, 0} when trying to print images while offline. This happens because:

1. Network requests fail and return nil data
2. Images are created with invalid dimensions (e.g., width=472, height=0)
3. UIGraphicsBeginImageContextWithOptions crashes when called with invalid dimensions

Solution

Added comprehensive validation in the iOS image processing pipeline:

• ImageManager.m: Added checks for nil data, invalid image dimensions, and prevent division by zero
• ThePrinter.m: Added validation at each step of image processing and return EPOS2_ERR_PARAM instead of crashing

Changes

• ✅ Validate image data before creating UIImage
• ✅ Check image dimensions before size calculations
• ✅ Validate calculated sizes before graphics context creation
• ✅ Return proper error codes instead of crashing

Testing

• TypeScript type checking passes
• ESLint passes
• Changes are in native iOS code only (no JavaScript changes)

Breaking Changes

None. This is a bug fix that improves error handling.

Checklist

• Code follows the project's coding standards
• Changes are focused and related to the issue
• Commit message follows conventional commits format
• No breaking changes introduced

[tr3v3r]

Hello @tolypash

Thank you very much for the contribution!

I've made a short review and added a couple of comments. Please check once you have time.

[tolypash]

Happy to contribute
Thanks @tr3v3r for the review, can you please check again now after my changes :)

[tr3v3r]

Just released a new version.
@tolypash