Fix CI failures: add vk-bootstrap submodule and fix MSYS2 stormlib

- Add vk-bootstrap as a git submodule (was in extern/ but not tracked,
  causing "vk-bootstrap not found" on all CI jobs)
- Whitelist extern/vk-bootstrap in .gitignore
- Move stormlib to a separate optional install step on both Windows CI
  jobs (mingw-w64-x86_64-stormlib doesn't exist in MSYS2 repos)

.github/workflows/build.yml

@@ -189,9 +189,12 @@ jobs:
             mingw-w64-clang-aarch64-vulkan-loader
             mingw-w64-clang-aarch64-vulkan-headers
             mingw-w64-clang-aarch64-shaderc
-            mingw-w64-clang-aarch64-stormlib
             git
 
+      - name: Install optional packages
+        shell: msys2 {0}
+        run: pacman -S --noconfirm --needed mingw-w64-clang-aarch64-stormlib || true
+
       - name: Configure
         shell: msys2 {0}
         run: cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
@@ -248,10 +251,13 @@ jobs:
             mingw-w64-x86_64-vulkan-loader
             mingw-w64-x86_64-vulkan-headers
             mingw-w64-x86_64-shaderc
-            mingw-w64-x86_64-stormlib
             mingw-w64-x86_64-nsis
             git
 
+      - name: Install optional packages
+        shell: msys2 {0}
+        run: pacman -S --noconfirm --needed mingw-w64-x86_64-stormlib || true
+
       - name: Configure
         shell: msys2 {0}
         run: cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release

.gitignore

@@ -46,6 +46,7 @@ wowee
 extern/*
 !extern/.gitkeep
 !extern/imgui
+!extern/vk-bootstrap
 
 # ImGui state
 imgui.ini

.gitmodules

@@ -2,3 +2,7 @@
 	path = extern/imgui
 	url = https://github.com/ocornut/imgui.git
 	shallow = true
+[submodule "extern/vk-bootstrap"]
+	path = extern/vk-bootstrap
+	url = https://github.com/charles-lunarg/vk-bootstrap.git
+	shallow = true

extern/vk-bootstrap

@@ -0,0 +1 @@
+Subproject commit 4d622d8550b3ba9ba1e998b01a469fb387e33ffd