v4.1.0

• Following the transition from a compiled to a header-only library, the target_compile_options previously applied to
  the compiled library were mistakenly propagated to all programs linking against the header-only library.
  This issue is now fixed by removing those flags and explicitly adding them to tests and examples. As a result,
  executable targets no longer inherit flags from the library.
• Removed unnecessary template specializations and merged their logic into the primary template
  for ArgSizeCalculator, Encoder, and Decoder using if constexpr.
• Eliminated <functional> header dependency in the frontend
• Replaced %(structured_keys) with %(named_args) in the PatternFormatter. This change now appends the
  entire key-value pair of named args to the message, not just the names.
• Relocated certain classes to the detail namespace
• Replaced sprintf with snprintf to fix macOS warning.
• Reviewed and removed gcc cold attribute from a few functions.
• Minor backend thread optimisations when logging c style strings or char arrays
• Improved backend thread variable and function names and fixed a bug for an edge case when the transit event hard limit is reached