R4 - Vulkan Backend, Infix Standard Library Improvements, and Documentation Updates

Vulkan Backend (VkExpr)

• Added a new Vulkan-based backend (VkExpr) for GPU acceleration. 715a47e, bc2ee49, f73517d, 643e674, 1de85ba, 74696a6, 40fa091, b461aa6

Infix & Standard Library

• Refactored input/output format macros ($\huge\color{red}Breaking \space Change$). Replaced get_fmt/__*_FMT__ with get_sampletype, __INPUT_SAMPLETYPE_*__, and __OUTPUT_SAMPLETYPE__ to clarify that they return integer constants representing sample types. e2525fc
• Added __COLOR_FAMILY__ macro and get_color_family() standard library function. e2525fc
• Added __NUM_PLANES__ family of macros (__NUM_PLANES__, __NUM_PLANES_0__, etc.) for accessing the number of planes in input clips. 8ecd6a8
• Improved get_width() and get_height() to correctly handle plane indices. 8ecd6a8

Documentation & Tooling

• Updated VSCode plugin to highlight the new __GPU__ macro. 643e674
• Clarified pixel read-after-write behavior in documentation. 73063fd
• Fixed LaTeX rendering issues in documentation. ce6b91c
• Various documentation improvements and clarifications. 76f38b7, 4c5c7fa

Bug Fixes

• Fix "Fails to build Preprocessor with Clang 20 on Fedora 42" (#9). badbc42

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Note for RC Users

• Improved VkExpr control flow performance. 74696a6, 40fa091, b461aa6

Full Changelog: R3.3...R4