Remove the any contrib library

[nyibbang]

Summary

This change completely removes the any contrib library and replaces its use with std::any available in C++17.

Motivation

This change has several benefits:

• It removes code from the project and uses the standard version instead.
• It removes a warning about a deprecated use of std::aligned_storage when compiling a project using the library in C++23 or more.

Impact on API

This change removes a header and replaces uses of linb::any with std::any in safe_any.hpp. In theory, if contrib/any.hpp is considered an implementation details of BT::Any then this should not be considered an API break as the interface of the class does not change.

Summary by CodeRabbit

Release Notes

• Refactor
  • Updated internal dependencies to use standard library components, improving code maintainability and reducing custom implementation overhead while maintaining full backward compatibility.

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[coderabbitai]

📝 Walkthrough

Walkthrough

The pull request removes a custom C++11-compatible any implementation (linb::any) from the contrib directory and migrates the BT::Any class to use the standard library's std::any, eliminating custom type-erasure machinery and external dependencies.

Changes

Cohort / File(s)	Summary
Removal of custom any implementation include/behaviortree_cpp/contrib/any.hpp	Complete file deletion (557 lines). Removes linb::any class, linb::bad_any_cast exception, in_place_type_t utilities, any_cast overloads, swap function, make_any helpers, internal VTable system, and type erasure logic.
Migration to std::any include/behaviortree_cpp/utils/safe_any.hpp	Replaced internal storage _any from linb::any to std::any. Updated all linb::any_cast calls to std::any_cast. Changed empty() method to use !_any.has_value() instead of _any.empty(). Modified constructor conversions, stringToNumber, enum/arithmetic handlers, and tryCast to operate on std::any. Added #include and removed contrib/any.hpp dependency.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

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🐰 Out with the old, in with the new,
Custom any code bids adieu,
std::any takes its rightful place,
Standard library saves the day with grace,
Simpler, cleaner, no more strife! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly and clearly describes the main change: removing the any contrib library.
Description check	✅ Passed	The description provides summary, motivation, and API impact analysis, but lacks discussion of testing strategy and other PR template sections.

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✨ Finishing touches

• 📝 Generate docstrings

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[facontidavide]

Thanks but this will probably affect the ABI and I will not do it.

Additionally, the implementation I use has a guaranteed 16 bytes small object optimization and I rely on that

[nyibbang]

Fair enough, would you be open to a PR to remove the use of aligned_storage in that case ?