feat: add TokenNftTransfer equality operator

[cheese-cakee]

Description

This PR adds operator== support to TokenNftTransfer and unit coverage for equality behavior, following the existing SDK value-type pattern.

Related Issue

• Fixes [Beginner]: Add operator== to TokenNftTransfer #1299

What Changed

• Added friend equality declaration to:
  • src/sdk/main/include/TokenNftTransfer.h
• Implemented equality operator in:
  • src/sdk/main/src/TokenNftTransfer.cc
• Extended unit tests in:
  • src/sdk/tests/unit/TokenNftTransferUnitTests.cc

Equality compares exactly these fields:

• mNftId
• mSenderAccountId
• mReceiverAccountId
• mIsApproval

Test Coverage Added

• Two default-constructed instances are equal
• Two identically-constructed instances are equal
• Instances with different mNftId are not equal
• Instances with different mSenderAccountId are not equal
• Instances with different mReceiverAccountId are not equal
• Instances with different mIsApproval are not equal

Notes

• Scope is limited to the issue-requested files only.
• No API behavior changes beyond adding equality support for TokenNftTransfer.

[github-actions]

Hey @cheese-cakee 👋 thanks for the PR!
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✅ DCO Sign-off -- All commits have valid sign-offs. Nice work!

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✅ Issue Link -- Linked to #1299 (assigned to you).

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[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 10 complexity · 0 duplication

Metric	Results
Complexity	10
Duplication	0

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_{TIP This summary will be updated as you push new changes. Give us feedback}

[rwalworth]

LGTM - the implementation is clean and correct, and the test coverage is solid. Left one small nitpick below on test naming, but nothing blocking. Running the workflows now and will merge once they pass!

[github-actions]

👋 Hi @cheese-cakee! Great work on your recent contribution! 🎉

Here are some issues you might want to explore next:

• [Intermediate]: Re-enable Dynamic Address Book (DAB) E2E Tests
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• [Intermediate]: Add HIP-869 Dynamic Address Book Example
• [Advanced]: Add Recovery ID Calculation for Ethereum Transaction Signing
• [Intermediate]: Consolidate std::string_view Usage

Happy coding! 🚀

[cheese-cakee]

Sorry I couldn't get back to solve the test naming issue on time! Thanks for merging tho :)