Add Web-Safe 64-bit Integer Fallbacks for Dart/Flutter Web

[codeZe-us]

The Dart implementation natively handles 64-bit integers on mobile/desktop, but compiling to Flutter Web forces integers into JavaScript Number types, leading to precision loss for large MEMO_IDs.

• Implement a conditional compilation or BigInt wrapper specifically for Dart Web targets in core-dart.
• Ensure that large routing IDs (> Number.MAX_SAFE_INTEGER) are safely parsed as strings when running in a browser context.
• Create specific Flutter Web test vectors.

Expectation: Developers using stellar_address_kit in Flutter Web apps do not experience silent truncation or precision loss for massive routing IDs.

Contributor telegram group: https://t.me/+OBaYnjDFA3w0Njdk

[Emoji-dot]

@Emoji-dot has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue

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[NickiM84]

@NickiM84 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello, I'm a fullStack developer with years of experience, I have worked on several projects, can I please work on this

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[Peaostrel]

@Peaostrel has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

i can handle this quickly

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[Okorie2000-code]

@Okorie2000-code has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer, can I work on this?

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[drips-wave]

Congratulations, @Emoji-dot! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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