Automated fix by @leftibot.

What changed

Fix #378: Replace hand-rolled number parsing with std::from_chars
The custom parse_num floating-point implementation produced slightly
different results from the C++ compiler's own literal parsing (e.g.
1.1e-4 was off by a few ULPs). Replace it with std::from_chars which
is locale-independent and matches compiler precision exactly. Also
migrate integer parsing in buildInt from std::stoll/stoull to
std::from_chars, fix the JSON number parser to pass the full numeric
string to from_chars instead of splitting mantissa/exponent and using
std::pow, and update parse_string to use from_chars for arithmetic types.
Co-Authored-By: Claude Opus 4.6 (1M context) [email protected]

Files

 CMakeLists.txt                                    |  4 ++
 include/chaiscript/chaiscript_defines.hpp         | 47 ++---------------
 include/chaiscript/dispatchkit/bootstrap.hpp      | 14 ++++--
 include/chaiscript/language/chaiscript_parser.hpp | 61 ++++++++++++-----------
 include/chaiscript/utility/json.hpp               | 16 +++---
 unittests/float_literal_test.cpp                  | 52 +++++++++++++++++++
 6 files changed, 110 insertions(+), 84 deletions(-)

Closes #378

Triggered by @lefticus.