Fix #3: Add random number generator

[leftibot]

Automated fix by @leftibot.

What changed

Fix #3: Add random number generator module
Add chaiscript::extras::random providing rand(), rand(max), rand(min, max),
and srand(seed) functions using C++11's facilities (std::mt19937
with std::uniform_int_distribution). The engine state is shared via
std::shared_ptr so srand() produces deterministic sequences. Also add
CATCH_CONFIG_NO_POSIX_SIGNALS to test files to fix SIGSTKSZ build errors
on newer glibc.
Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com

Files

 include/chaiscript/extras/random.hpp | 41 ++++++++++++++++++++++++++++++
 tests/CMakeLists.txt                 |  6 +++++
 tests/math.cpp                       |  1 +
 tests/random.cpp                     | 48 ++++++++++++++++++++++++++++++++++++
 tests/string_methods.cpp             |  1 +
 5 files changed, 97 insertions(+)

Closes #3

Triggered by @lefticus.

[lefticus]

@leftibot make this more like the C++ interface, where the user has to have the random number generator engine, and they can copy / seed it / etc, and then ask for values from it from a range, etc.

[leftibot]

Addressed review feedback from @lefticus. New commits:

97843be Address review: expose Random_Engine type mirroring C++ <random> interface

[lefticus]

@leftibot make it clear what random device is being used in the name of the random device.

[leftibot]

Addressed review feedback from @lefticus. New commits:

955b4ba Address review: rename Random_Engine to MT19937_Engine