docs: add 'Limitations' section to README.md

Author: EchoEllet

README.md

@@ -147,6 +147,14 @@ $ swift-format format --in-place --recursive macos/native_image_picker_macos/Sou
 
 Contributions are welcome. File issues to the [GitHub repo](https://github.com/CompileKernel/native-image-picker-macos).
 
+## ℹ️ Limitations
+
+* [Similarly to `image_picker_macos`](https://pub.dev/packages/image_picker_macos#limitations), `ImageSource.camera` is not supported [unless a `cameraDelegate` is set](https://pub.dev/packages/image_picker#windows-macos-and-linux).
+* [Similarly to `image_picker_macos`](https://pub.dev/packages/image_picker_macos#pickvideo), the `maxDuration` argument in `pickVideo` is unsupported and will be silently ignored.
+
+> [!WARNING]
+> **Known issue**: The native picker window initially appears smaller than expected, requiring the user to manually resize it. Refer to [#2](https://github.com/CompileKernel/native-image-picker-macos/issues/2) for details.
+
 ## 📚 Additional information
 
 This functionality was originally proposed as a [pull request to `image_picker_macos`](https://github.com/flutter/packages/pull/8079/), but it was later decided to split it into a community package which is unendorsed.