Add missing cmath include

[ethanmusser]

This header is required due to usage of std::abs in this source file.

See e.g. this failing CI run for the corresponding error, which is as follows.

Processing ./.
  Installing build dependencies: started
  Installing build dependencies: finished with status 'done'
  Getting requirements to build wheel: started
  Getting requirements to build wheel: finished with status 'done'
  Preparing metadata (pyproject.toml): started
  Preparing metadata (pyproject.toml): finished with status 'done'
Building wheels for collected packages: libmultisense
  Building wheel for libmultisense (pyproject.toml): started
  Building wheel for libmultisense (pyproject.toml): finished with status 'error'
  error: subprocess-exited-with-error
  
  × Building wheel for libmultisense (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [96 lines of output]
      *** scikit-build-core 1.1.0 using CMake 4.4.3 (wheel)
      *** Configuring CMake...
      loading initial cache file /var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/tmp64epq3l8/build/CMakeInit.txt
      -- The C compiler identification is Clang 23.1.0
      -- The CXX compiler identification is Clang 23.1.0
      -- Detecting C compiler ABI info
      -- Detecting C compiler ABI info - done
      -- Check for working C compiler: /opt/homebrew/opt/llvm/bin/clang - skipped
      -- Detecting C compile features
      -- Detecting C compile features - done
      -- Detecting CXX compiler ABI info
      -- Detecting CXX compiler ABI info - done
      -- Check for working CXX compiler: /opt/homebrew/opt/llvm/bin/clang++ - skipped
      -- Detecting CXX compile features
      -- Detecting CXX compile features - done
      -- Performing Test HAVE_STD_FILESYSTEM
      -- Performing Test HAVE_STD_FILESYSTEM - Success
      -- Performing Test HAVE_CONSTEXPR
      -- Performing Test HAVE_CONSTEXPR - Success
      -- Found nlohmann_json: /opt/homebrew/share/cmake/nlohmann_json/nlohmann_jsonConfig.cmake (found suitable version "3.12.0", minimum required is "3.9")
      -- Building JSON serialization helper functions
      -- Looking for vasprintf
      -- Looking for vasprintf - found
      -- Performing Test CMAKE_HAVE_LIBC_PTHREAD
      -- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
      -- Found Threads: TRUE
      CMake Warning (author) at /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/FindPythonLibsNew.cmake:101 (message):
        Policy CMP0148 is not set: The FindPythonInterp and FindPythonLibs modules
        are removed.  Run "cmake --help-policy CMP0148" for policy details.  Use
        the cmake_policy command to set the policy and suppress this warning, or
        preferably upgrade to using FindPython, either by calling it explicitly
        before pybind11, or by setting PYBIND11_FINDPYTHON ON before pybind11.
      Call Stack (most recent call first):
        /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/pybind11Tools.cmake:44 (find_package)
        /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/pybind11Common.cmake:243 (include)
        /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/pybind11Config.cmake:257 (include)
        python/CMakeLists.txt:4 (find_package)
      This warning is for project developers.  Use -Wno-author to suppress it.
      
      CMake Warning (deprecated) at /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/FindPythonLibsNew.cmake:110 (cmake_policy):
        The OLD behavior for policy CMP0148 will be removed from a future version
        of CMake.
      
        The cmake-policies(7) manual explains that the OLD behaviors of all
        policies are deprecated and that a policy should be set to OLD only under
        specific short-term circumstances.  Projects should be ported to the NEW
        behavior and not rely on setting a policy to OLD.
      Call Stack (most recent call first):
        /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/pybind11Tools.cmake:44 (find_package)
        /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/pybind11Common.cmake:243 (include)
        /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/share/cmake/pybind11/pybind11Config.cmake:257 (include)
        python/CMakeLists.txt:4 (find_package)
      This warning is for project developers.  Use -Wno-author or -Wno-deprecated
      to suppress it.
      
      -- Found PythonInterp: /Users/runner/work/LibMultiSense/LibMultiSense/.venv/bin/python3 (found suitable version "3.14.7", minimum required is "3.9")
      -- Found PythonLibs: /opt/homebrew/opt/[email protected]/Frameworks/Python.framework/Versions/3.14/Python
      -- Performing Test HAS_FLTO_THIN
      -- Performing Test HAS_FLTO_THIN - Success
      -- Performing Test HAS_FLTO
      -- Performing Test HAS_FLTO - Success
      -- Found pybind11: /private/var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/pip-build-env-1xnfh1z_/overlay/lib/python3.14/site-packages/pybind11/include (found version "3.1.0")
      Building python bindings with json print support
      -- Configuring done (4.0s)
      -- Generating done (0.0s)
      -- Build files have been written to: /var/folders/36/tjdph2t965j8snz9_vkdnw0r0000gn/T/tmp64epq3l8/build
      *** Building project with Ninja...
      [1/20] Building CXX object source/Wire/CMakeFiles/MultiSenseWire.dir/source/utility/TimeStamp.cc.o
      [2/20] Building CXX object source/Wire/CMakeFiles/MultiSenseWire.dir/source/utility/Exception.cc.o
      [3/20] Building CXX object source/LibMultiSense/CMakeFiles/MultiSense.dir/details/factory.cc.o
      [4/20] Linking CXX static library source/Wire/libMultiSenseWire.a
      [5/20] Building CXX object source/LibMultiSense/CMakeFiles/MultiSense.dir/details/multi_channel.cc.o
      [6/20] Building CXX object source/LibMultiSense/CMakeFiles/MultiSense.dir/details/legacy/calibration.cc.o
      FAILED: [code=1] source/LibMultiSense/CMakeFiles/MultiSense.dir/details/legacy/calibration.cc.o
      /opt/homebrew/opt/llvm/bin/clang++ -DCRL_HAVE_CONSTEXPR -DMultiSense_STATIC -I/Users/runner/work/LibMultiSense/LibMultiSense/source/LibMultiSense/include -I/Users/runner/work/LibMultiSense/LibMultiSense/source/Shared -I/Users/runner/work/LibMultiSense/LibMultiSense/source/Wire/include -isystem /opt/homebrew/include -O3 -DNDEBUG -std=gnu++17 -arch arm64 -fPIC -Wall -Wextra -Werror -Wpedantic -Wno-variadic-macros -Wno-gnu-zero-variadic-macro-arguments -MD -MT source/LibMultiSense/CMakeFiles/MultiSense.dir/details/legacy/calibration.cc.o -MF source/LibMultiSense/CMakeFiles/MultiSense.dir/details/legacy/calibration.cc.o.d -o source/LibMultiSense/CMakeFiles/MultiSense.dir/details/legacy/calibration.cc.o -c /Users/runner/work/LibMultiSense/LibMultiSense/source/LibMultiSense/details/legacy/calibration.cc
      /Users/runner/work/LibMultiSense/LibMultiSense/source/LibMultiSense/details/legacy/calibration.cc:48:93: error: no member named 'abs' in namespace 'std'; did you mean 'std::chrono::abs'?
         48 |     if (cal.M[0][0] < 0.1 || cal.M[0][2] < 0.1 || cal.M[1][1] < 0.1 || cal.M[1][2] < 0.1 || std::abs(cal.D[0]) < 1e-10)
            |                                                                                             ^~~~~~~~
            |                                                                                             std::chrono::abs
      /opt/homebrew/Cellar/llvm/23.1.0/bin/../include/c++/v1/__chrono/time_point.h:132:78: note: 'std::chrono::abs' declared here
        132 | [[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI constexpr duration<_Rep, _Period> abs(duration<_Rep, _Period> __d) {
            |                                                                              ^
      /Users/runner/work/LibMultiSense/LibMultiSense/source/LibMultiSense/details/legacy/calibration.cc:48:98: error: no matching function for call to 'abs'
         48 |     if (cal.M[0][0] < 0.1 || cal.M[0][2] < 0.1 || cal.M[1][1] < 0.1 || cal.M[1][2] < 0.1 || std::abs(cal.D[0]) < 1e-10)
            |                                                                                                  ^~~
      /opt/homebrew/Cellar/llvm/23.1.0/bin/../include/c++/v1/__chrono/time_point.h:132:78: note: candidate template ignored: could not match 'duration<_Rep, _Period>' against 'float'
        132 | [[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI constexpr duration<_Rep, _Period> abs(duration<_Rep, _Period> __d) {
            |                                                                              ^
      2 errors generated.
      [7/20] Building CXX object source/LibMultiSense/CMakeFiles/MultiSense.dir/details/utilities.cc.o
      [8/20] Building CXX object source/LibMultiSense/CMakeFiles/MultiSense.dir/details/secondary_application.cc.o
      [9/20] Building CXX object source/LibMultiSense/CMakeFiles/MultiSense.dir/details/legacy/configuration.cc.o
      [10/20] Building CXX object source/LibMultiSense/CMakeFiles/MultiSense.dir/details/legacy/channel.cc.o
      ninja: build stopped: subcommand failed.
      
      *** CMake build failed
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for libmultisense
ERROR: Failed to build one or more wheels
Failed to build libmultisense

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