docs: fill out compat, lvglh, and toolchain documentation

Replace placeholder content in doc/compat/, doc/lvglh/, and
doc/toolchain/ with comprehensive documentation derived from the
source files.

- compat: document Wasuro WASM VM compatibility shims
- lvglh: document LVGL v9.2.2 configuration, fonts, and patches
- toolchain: document all 13 build pipeline scripts

doc/toolchain/compile_isogen.md

@@ -1 +1,37 @@
-# Placeholder
+# compile_isogen.sh
+
+Creates a bootable GRUB ISO image containing the Asuro kernel.
+
+## Overview
+
+`compile_isogen.sh` copies the compiled kernel binary into the ISO directory structure and invokes `grub-mkrescue` to produce a bootable CD-ROM image. The resulting `Asuro.iso` can be booted in any x86 emulator (QEMU, VirtualBox, etc.) or written to physical media.
+
+## Prerequisites
+
+- `grub-mkrescue` (from GRUB utilities) and `xorriso` (its backend) must be available.
+- `bin/kernel.bin` must exist (produced by `compile_link.sh`).
+- The `iso/boot/` directory must exist and contain a GRUB configuration file (`iso/boot/grub/grub.cfg`).
+
+## Inputs
+
+| Source | Description |
+|--------|-------------|
+| `bin/kernel.bin` | The linked kernel binary. |
+| `iso/` | Pre-existing ISO directory tree with GRUB configuration. |
+
+## Outputs
+
+| File | Description |
+|------|-------------|
+| `Asuro.iso` | Bootable GRUB rescue ISO image. |
+| `iso/boot/asuro.bin` | Copy of the kernel binary placed into the ISO tree. |
+
+## Behavior
+
+1. Copies `bin/kernel.bin` to `iso/boot/asuro.bin`.
+2. Runs `grub-mkrescue -o Asuro.iso iso` to generate the bootable ISO from the `iso/` directory tree.
+
+## Notes
+
+- The GRUB configuration in `iso/boot/grub/grub.cfg` must reference `asuro.bin` as the kernel to load.
+- The ISO is generated in the project root directory.