feat: project skeleton, core types and math with transform tests

cmake/plot_options.cmake

@@ -0,0 +1,33 @@
+# Shared build options and warning policy for the plot project.
+#
+# Included by the top-level CMakeLists.txt; every subdirectory target is
+# expected to run plot_apply_warnings(<target>) so the core stays warning-clean
+# under -Wall -Wextra -Wpedantic -Wconversion -Wshadow.
+
+if(CMAKE_VERSION VERSION_LESS 3.24)
+  message(FATAL_ERROR "plot requires CMake 3.24 or newer (found ${CMAKE_VERSION})")
+endif()
+
+# Adapters and examples pull in third-party SDKs, so they default to OFF; the
+# core library and its tests build on a bare toolchain.
+option(PLOT_BUILD_TESTS "Build the plot test suite" ON)
+option(PLOT_BUILD_EXAMPLES "Build the example programs" OFF)
+option(PLOT_BUILD_GLFW "Build the GLFW adapter and demo" OFF)
+option(PLOT_BUILD_IMGUI "Build the Dear ImGui adapter and demo" OFF)
+option(PLOT_BUILD_QT6 "Build the Qt6 adapter and demo" OFF)
+option(PLOT_BUILD_GTK4 "Build the GTK4 adapter and demo" OFF)
+
+# Apply the project warning set to a first-party target. Warnings are never
+# suppressed per file.
+function(plot_apply_warnings target)
+  if(MSVC)
+    target_compile_options(${target} PRIVATE /W4 /permissive-)
+  else()
+    target_compile_options(${target} PRIVATE
+      -Wall
+      -Wextra
+      -Wpedantic
+      -Wconversion
+      -Wshadow)
+  endif()
+endfunction()