work around a panick during handbook's pdf generation

Handbook/GNUmakefile

@@ -368,7 +368,7 @@ install-build-deps:
 	@cargo install mdbook --version "0.4.49" --locked
 	@cargo install xq --vers "^0.4" --locked
 	@cargo install mdbook-alerts --vers "^0.7" --locked
-	@cargo install mdbook-pdf --vers "^0.1" --locked
+	@cargo install mdbook-pdf --vers "0.1.11" --locked
 ifeq ($(SG_BUILD_PLATFORM),$(SG_BUILD_PLATFORM_LINUX))
 	@echo "Installing mdbook-pdf-outline..."
 	@python -m venv $(VIRTUAL_ENV) \

Handbook/src/appendix/changelog.md

@@ -13,6 +13,10 @@ This patch release addresses a severe regression affecting UE `5.5` projects wit
 
 - Resolved a critical deadlock between the rendering and game threads in Unreal Engine `5.5` that when `IHeadMountedDisplay::GetHMDMonitorInfo()` is invoked from `FSGXRTracker::GetControllerTransform()` in certain conditions; specifically while SenseCom is running and gloves are present and connected. This issue is [related to critical deadlock issue (UE-212224), occurring during PipelinedFrameState acquisition, which had already been addressed for the plugin versions running on UE `5.6+`](#260---2025-06-04). Because it only gets triggered under specific project settings, we were previously unaware that it also affected IHeadMountedDisplay::GetHMDMonitorInfo() in UE 5.5.
 
+### Documentation
+
+- Locked the [mdbook-pdf](https://github.com/HollowMan6/mdbook-pdf) crate to [`v0.1.11`](https://github.com/HollowMan6/mdbook-pdf/releases/tag/v0.1.11) due to the following `v0.1.12` panick during PDF generation: called `Result::unwrap()` on an `Err` value: Unable to deserialize the `RenderContext`.
+
 ## [2.7.0] - 2025-11-18
 
 This minor release focuses on delivering performance improvements, made possible by major optimizations in the underlying proprietary SenseGlove libraries, while also introducing some breaking changes.