repo: AGENTS.md, GLEW 2.3.1 upgrade, Filament version bump, style tooling

- Add AGENTS.md with coding and PR review guidelines
- GLEW upgraded to v2.3.1 (adds GL_EXT_memory_object, GL_EXT_semaphore for
  Vulkan-OpenGL interop needed by Gaussian splatting)
- Filament version bump for shared-context platform header support
- Style tooling: check_style.py and check_cpp_style.cmake updated for .comp
  (GLSL compute) and .mm (Objective-C++) file handling

Author: ssheorey

.gitignore

@@ -91,3 +91,5 @@ docs/Doxyfile
 docs/getting_started.rst
 docs/docker.rst
 docs/tensorboard.md
+
+resources

3rdparty/README.md

@@ -63,7 +63,7 @@ A C++ library for performing fast approximate nearest neighbor searches in high
 dimensional spaces
 http://www.cs.ubc.ca/research/flann/
 --------------------------------------------------------------------------------
-GLEW                        2.1.0                                    MIT License
+GLEW                        2.3.1                                    MIT License
 A cross-platform open-source C/C++ extension loading library
 http://glew.sourceforge.net/
 --------------------------------------------------------------------------------

3rdparty/filament/filament_build.cmake

@@ -53,8 +53,7 @@ endif()
 ExternalProject_Add(
     ext_filament
     PREFIX filament
-    URL https://github.com/google/filament/archive/refs/tags/v1.54.0.tar.gz
-    URL_HASH SHA256=f4cb4eb81e3a5d66a9612ac131d16183e118b694f4f34c051506c523a8389e8d
+    URL https://github.com/google/filament/archive/refs/tags/v1.57.2.tar.gz
     DOWNLOAD_DIR "${OPEN3D_THIRD_PARTY_DOWNLOAD_DIR}/filament"
     UPDATE_COMMAND ""
     CMAKE_ARGS

3rdparty/filament/filament_download.cmake

@@ -21,8 +21,8 @@ else()
             string(APPEND lib_dir /x86_64/md)
         endif()
     elseif(APPLE)
-        set(FILAMENT_URL https://github.com/google/filament/releases/download/v1.54.0/filament-v1.54.0-mac.tgz)
-        set(FILAMENT_SHA256 9b71642bd697075110579ccb55a2e8f319b05bbd89613c72567745534936186e)
+        set(FILAMENT_URL https://github.com/google/filament/releases/download/v1.57.2/filament-v1.57.2-mac.tgz)
+        set(FILAMENT_SHA256 e827a00d7433aee45397d99d98dbe7bbe78b6cc89cb76b7b105d48d5bab4d655)
     else()      # Linux: Check glibc version and use open3d filament binary if new (Ubuntu 20.04 and similar)
         execute_process(COMMAND ldd --version OUTPUT_VARIABLE ldd_version)
         string(REGEX MATCH "([0-9]+\.)+[0-9]+" glibc_version ${ldd_version})