feat: add OpenGL abstraction layer with RAII resources

- Replace window class with cbt::opengl::context
- Add buffer resource (VBO, EBO, UBO, SSBO) with move semantics
- Add texture resource with format/type enums and filtering
- Add descriptor_set for Vulkan-style resource binding
- All resources use RAII with proper cleanup

deps/Findglm.cmake

@@ -0,0 +1,75 @@
+# ==============================================================================
+# Find glm
+# ==============================================================================
+# This module fetches the GLM (OpenGL Mathematics) library.
+#
+# Targets provided:
+#   glm::glm - The glm library target
+#
+# Variables set:
+#   glm_FOUND       - TRUE if glm is available
+#   glm_LIBRARIES   - The glm library target (glm::glm)
+#   glm_INCLUDE_DIR - Include directories for glm
+#   glm_VERSION     - Version of glm (if available)
+# ==============================================================================
+
+if (DEFINED _FINDGLM_INCLUDED)
+    return()
+endif()
+set(_FINDGLM_INCLUDED TRUE)
+
+# Use the version passed to find_package(), or default to 1.0.1
+if (DEFINED glm_FIND_VERSION AND NOT glm_FIND_VERSION STREQUAL "")
+    set(GLM_VERSION "${glm_FIND_VERSION}")
+else()
+    set(GLM_VERSION "1.0.1")
+endif()
+
+message(STATUS "Fetching glm ${GLM_VERSION}")
+
+include(FetchContent)
+
+find_program(GIT_EXECUTABLE git)
+if (GIT_EXECUTABLE)
+    set(GLM_FETCH_METHOD "GIT")
+else()
+    message(FATAL_ERROR "Fetch with zip not supported.")
+endif()
+
+set(_glm_warn_deprecated "${CMAKE_WARN_DEPRECATED}")
+set(CMAKE_WARN_DEPRECATED OFF CACHE BOOL "Suppress deprecated warnings while fetching glm" FORCE)
+
+if (GLM_FETCH_METHOD STREQUAL "GIT")
+    FetchContent_Declare(
+        glm
+        GIT_REPOSITORY https://github.com/g-truc/glm.git
+        GIT_TAG        ${GLM_VERSION}
+    )
+endif()
+
+FetchContent_MakeAvailable(glm)
+
+set(CMAKE_WARN_DEPRECATED "${_glm_warn_deprecated}" CACHE BOOL "Restore deprecation warnings" FORCE)
+
+if (NOT TARGET glm::glm)
+    if (TARGET glm)
+        add_library(glm::glm ALIAS glm)
+    else()
+        message(FATAL_ERROR "Could not fetch glm; no target glm or glm::glm available")
+    endif()
+endif()
+
+set(glm_FOUND        TRUE)
+set(glm_LIBRARIES    glm::glm)
+set(glm_VERSION      "${GLM_VERSION}")
+get_target_property(_glm_inc glm::glm INTERFACE_INCLUDE_DIRECTORIES)
+set(glm_INCLUDE_DIR  "${_glm_inc}")
+
+# Mark glm includes as SYSTEM to suppress warnings from its headers
+if (_glm_inc AND TARGET glm)
+    set_target_properties(glm PROPERTIES
+        INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${_glm_inc}"
+    )
+endif()
+
+set(GLM_LICENSE_FILE "${glm_SOURCE_DIR}/copying.txt" CACHE FILEPATH "Path to GLM license file")