[node] Fix logging mutex crash at exit on macOS

[Copilot]

Fixes crash at OrtReleaseEnv on macOS (and other libc platforms) caused by mutex destruction order issues in the default logger.

Solution: Refactor Node.js binding to use Meyer's Singleton pattern for ORT environment lifecycle, intentionally leaking Ort::Env at program exit to avoid destructor ordering problems.

Implementation:

• OrtSingletonData: Meyer's Singleton managing global Ort::Env and default Ort::RunOptions via function-local static
• OrtInstanceData: Per-environment N-API instance data for thread-local constructor references
• No explicit cleanup: Ort::Env never destroyed, eliminating OrtReleaseEnv call that triggered the crash

// Before: env destroyed at exit, causing mutex crash
std::unique_ptr<Ort::Env> env;  // Destructor calls OrtReleaseEnv

// After: function-local static leaks intentionally
OrtSingletonData::OrtObjects& OrtSingletonData::GetOrCreateOrtObjects(int log_level) {
  static OrtObjects ort_objects(log_level);  // Never destroyed
  return ort_objects;
}

Fixes #24579

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