[Feature] Add multi-platform safety

[austinn]

Description

Addresses: #19

This PR resolves issues when using the gaimon package in multi-platform Flutter applications (e.g. Web, macOS, Windows, Linux).

Previously, the package would:

1. Crash at runtime on Web with Unsupported operation: Platform._operatingSystem due to direct access to Platform.isAndroid (from dart:io).
2. Throw MissingPluginException at runtime on non-mobile platforms (macOS, Windows, Linux) when invoking any haptic action due to unguarded MethodChannel invocations.

Solution

• Introduced kIsWeb guards to safely short-circuit Platform checks on the Web.
• Guarded all MethodChannel invocations (_channel.invokeMethod) to ensure they are only triggered on supported mobile platforms (Android and iOS).
• Added try-catch safety to canSupportsHaptic to fallback to false in case of unexpected platform errors.
• Allowed Flutter SDK native methods (e.g., HapticFeedback.selectionClick(), HapticFeedback.heavyImpact()) to run untouched as they are natively stubbed/handled safely on all platforms by Flutter.
• Added a new unit test suite verifying that all calls run successfully without throwing exceptions on unsupported platforms (like macOS).

Documentation

Documented platform compatibility and fallback behavior in README.md

[istornz]

Thanks for you PR, I let some little comments 👍

[istornz]

I think this is enough, same for iOS

Suggested change

	static bool get _isAndroid => !kIsWeb && Platform.isAndroid;
	static bool get _isAndroid => Platform.isAndroid;

[austinn]

Sorry @istornz I'm not sure I'm following - web doesn't support the Platform API - so why wouldn't we add this before a native platform check?

[istornz]

Maybe adding the kIsWeb in this condition is better?

[austinn]

@istornz This package only supports Android and iOS, so I'm not sure why adding a kIsWeb would be useful here.

[austinn]

@istornz I don't think we need a specific kIsWeb check since any platform other than Android and iOS will safely fail using _supportsMethodChannel.

We still want to add the kIsWeb check before the Platform checks in case.

For context: the app I'm developing is available on Android, iOS, MacOS, and Web, so I needed this to fail gracefully on MacOS and Web, but still work on Android and iOS.