Merge branch 'develop' into claude/deep-copy-key-comp-5649

Conflicts:
- tests/src/unit-comparison.cpp: kept both sides' helpers (key_case_less/
  key_case_json/innermost from the PR, case_insensitive_less/ci_json from
  develop's #5720) and both new test cases

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/meta/type_traits.hpp

@@ -756,7 +756,7 @@ std::is_constructible <decltype(std::declval<Compare>()(std::declval<A>(), std::
 // avoid their instantiation on all compilers, even when the first operand
 // is false. The dispatch on is_json_pointer_of can be removed once the
 // deprecated json_pointer comparison operators have been removed.
-template<typename Compare, typename A, typename B, bool = is_json_pointer_of<A, B>::value>
+template<typename Compare, typename A, typename B, bool = is_json_pointer_of<uncvref_t<A>, uncvref_t<B>>::value>
 struct is_comparable : std::false_type {};
 
 template<typename Compare, typename A, typename B>