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/Findctre.cmake

@@ -0,0 +1,79 @@
+# ==============================================================================
+# Find ctre
+# ==============================================================================
+# This module fetches the CTRE (Compile Time Regular Expressions) library.
+#
+# Targets provided:
+#   ctre::ctre - The ctre library target
+#
+# Variables set:
+#   ctre_FOUND       - TRUE if ctre is available
+#   ctre_LIBRARIES   - The ctre library target (ctre::ctre)
+#   ctre_INCLUDE_DIR - Include directories for ctre
+#   ctre_VERSION     - Version of ctre (if available)
+# ==============================================================================
+
+if (DEFINED _FINDCTRE_INCLUDED)
+    return()
+endif()
+set(_FINDCTRE_INCLUDED TRUE)
+
+# Use the version passed to find_package(), or default to 3.10.0
+if (DEFINED ctre_FIND_VERSION AND NOT ctre_FIND_VERSION STREQUAL "")
+    set(CTRE_VERSION "${ctre_FIND_VERSION}")
+else()
+    set(CTRE_VERSION "3.10.0")
+endif()
+
+message(STATUS "Fetching ctre ${CTRE_VERSION}")
+
+include(FetchContent)
+
+find_program(GIT_EXECUTABLE git)
+if (GIT_EXECUTABLE)
+    set(CTRE_FETCH_METHOD "GIT")
+else()
+    message(FATAL_ERROR "Fetch with zip not supported.")
+endif()
+
+if (CTRE_FETCH_METHOD STREQUAL "GIT")
+    # Turn off BUILD_TESTING globally to prevent CTest from being included in CTRE
+    set(BUILD_TESTING OFF CACHE BOOL "Disable testing globally" FORCE)
+    # Set the CTRE_BUILD_TESTS option before including the CTRE library
+    set(CTRE_BUILD_TESTS OFF CACHE BOOL "Build ctre Tests" FORCE)
+    set(CTRE_BUILD_PACKAGE OFF CACHE BOOL "Build ctre Package" FORCE)
+
+    FetchContent_Declare(
+        ctre
+        GIT_REPOSITORY https://github.com/hanickadot/compile-time-regular-expressions.git
+        GIT_TAG        v${CTRE_VERSION}
+    )
+endif()
+
+FetchContent_MakeAvailable(ctre)
+
+# Turn BUILD_TESTING back on after including CTRE
+set(BUILD_TESTING ON CACHE BOOL "Enable testing globally" FORCE)
+
+if (NOT TARGET ctre::ctre)
+    if (TARGET ctre)
+        add_library(ctre::ctre ALIAS ctre)
+    else()
+        message(FATAL_ERROR "Could not fetch ctre; no target ctre or ctre::ctre available")
+    endif()
+endif()
+
+set(ctre_FOUND        TRUE)
+set(ctre_LIBRARIES    ctre::ctre)
+set(ctre_VERSION      "${CTRE_VERSION}")
+get_target_property(_ctre_inc ctre::ctre INTERFACE_INCLUDE_DIRECTORIES)
+set(ctre_INCLUDE_DIR  "${_ctre_inc}")
+
+# Mark ctre includes as SYSTEM to suppress warnings from its headers
+if (_ctre_inc AND TARGET ctre)
+    set_target_properties(ctre PROPERTIES
+        INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${_ctre_inc}"
+    )
+endif()
+
+set(CTRE_LICENSE_FILE "${ctre_SOURCE_DIR}/LICENSE" CACHE FILEPATH "Path to CTRE license file")