Add gpu compressed decoders (#12237) 195d4fcb25

* feat(renderer): GPU compressed texture support (BC7 / ASTC / ETC2)

- Software decoders for BC, ASTC, ETC2 in the decoders library.
- KTX2 reader extended to parse BC7, ASTC LDR (all footprints), ETC2 RGBA8.
- Ktx2HwSupport + per-backend cap flags; DecodeKtx2 falls back to SW
  decode + tight RGBA mip chain when HW lacks the format.
- Native compressed upload in Vulkan, GL, Metal, WebGPU
  (D3D11/D3D12 already supported BC7); per-mip uploads, no auto-mipgen
  for compressed.
- Texture compressor premultiplies alpha before BC7 encode so output
  matches the runtime PNG path.
- Android CMakeLists exposes decoders include directory.

* Android break

* fix(android): always expose decoders/include for renderer sources

* fix(decoders): include <cstdio> for stderr in texture_decoder.cpp

* Clang format

* Update premake5_pls_renderer.lua

* Update render_context_gl_impl.cpp

* Update render_context_vulkan_impl.cpp

* Fix null renderer

* Update decode_ktx2.hpp

* Update astc_footprints.hpp

* Copyright

* Update texture_decoder.cpp

* Comments

* Comments

* Update to ETC

* Update decode_bc_texture.cpp

* Update decode_bc_texture.cpp

* More comments

* Comments

* Bug fix on block sizes

* Clang format

* Fix ASTC

* Fix android

* Update UE and Other platform

* Update render_context_vulkan_impl.cpp

* Josh Comments

Co-authored-by: John White <aliasbinman@gmail.com>