add vk shaders source (+1 squashed commits)

Squashed commits:

[45359f49] add vk shaders source

.github/workflows/kcpp-build-release-win-full-cu12.yaml

@@ -84,3 +84,19 @@ jobs:
         with:
           name: kcpp_windows_pyinstallers
           path: dist/
+
+      - name: Generate VK Instructions
+        id: gen_vk_instructions
+        run: |
+          echo "If you cannot compile vulkan shaders yourself with glslc, you can manually patch in precompiled vulkan shader source files. Copy these 2 files to the ggml/src directory before building." > vulkan-readme.txt
+
+      - name: Save Standalone Vulkan Shaders
+        uses: actions/upload-artifact@v4
+        with:
+          name: vulkan_precompiled_shaders
+          path: |
+            ggml/src/ggml-vulkan-shaders.cpp
+            ggml/src/ggml-vulkan-shaders.hpp
+            vulkan-readme.txt
+
+