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/compat/types.md

@@ -1 +1,16 @@
-# Placeholder
+# types
+
+Empty compatibility shim that satisfies `uses types` references from the Wasuro WASM VM project.
+
+## Overview
+
+Some units in the Wasuro WASM VM source tree include `uses types` to pull in shared type definitions from the Asuro kernel. In the kernel proper, those types may be declared elsewhere or may no longer be needed in the WASM context. This stub unit provides an empty `types` compilation unit so that `uses types` resolves without error during the Wasuro build.
+
+## Dependencies
+
+None.
+
+## Notes
+
+- The unit declares no constants, types, variables, or routines. Its only purpose is to exist as a valid compilation unit.
+- If Wasuro code is ever updated to remove the `uses types` dependency, this shim can be deleted.