[dave-365]

Fixes #1746

Overview

When passing mismatched callback or finalizer signatures to methods such as Function::New, PropertyDescriptor::Accessor, Object::AddFinalizer, or ThreadSafeFunction::New, unconstrained templates would fail deep inside internal wrappers (such as details::CallbackData in napi-inl.h). This produced lengthy, cryptic template instantiation errors that were difficult to decipher.

This PR adopts C++20 Concepts () to enforce callable and finalizer signatures at the call site at compile time, providing immediate and readable compiler diagnostics while maintaining 100% backward compatibility for pre-C++20 builds.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.69%. Comparing base (25c6b21) to head (4dcfcc5).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1762      +/-   ##
==========================================
+ Coverage   63.68%   63.69%   +0.01%     
==========================================
  Files           3        3              
  Lines        2065     2066       +1     
  Branches      731      732       +1     
==========================================
+ Hits         1315     1316       +1     
  Misses        162      162              
  Partials      588      588              

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.