Vulkan/SPIR-V: update to 1.4.350.1.

[Rutpiv]

Testing the changes

• I tested the changes in this PR: briefly

Local build testing

• I built this PR locally for my native architecture, (x86_64-glibc)
• I built this PR locally for these architectures using specific masterdirs:
  • x86_64-musl
  • i686
• I built this PR locally for these architectures (crossbuilds):
  • aarch64
  • aarch64-musl
  • armv7l
  • armv7l-musl
  • armv6l
  • armv6l-musl

[Rutpiv]

Vulkan SDK 1.4.350.1

Coordinated bump of the Vulkan SDK stack to vulkan-sdk-1.4.350.1, with the
per-package fixes the bump exposed.

SPIRV-Headers — update 1.4.341.0 → 1.4.350.1.

SPIRV-Tools — update 2026.1 → 2026.2.

• Drop the .rc1 suffix from distfiles: the rc1 tag does not always point at
  the same commit as the final release (some cycles it was rc2), so pinning
  rc1 is fragile. Use the release tag v${version} instead.
• update adjusted to refs/tags/v\K[0-9]+\.[0-9]+, matching only
  major.minor so the rc tags aren't picked up.
• -devel subpackage now uses ${sourcepkg}>=${version}_${revision}.

Vulkan-Headers — update 1.4.341.0 → 1.4.350.1.

vulkan-loader — update 1.4.341.0 → 1.4.350.1.

• Drop libxkbcommon-devel (stale makedepend).
• Move the installed CMake config files to the -devel subpackage so
  find_package(VulkanLoader) resolves for consumers.

zeux-volk — update 1.4.341.0 → 1.4.350.1.

• Add depends=Vulkan-Headers: the public volk.h includes
  <vulkan/vulkan_core.h>, invisible to the SONAME scanner on a header-only +
  .a package.
• This drops its only in-tree consumer (Vulkan-Tools no longer pulls it).
  Keeping it regardless: it's an actively maintained dev library (Vulkan
  meta-loader) that belongs alongside the SDK, unlike robin-hood-hashing, which
  is discontinued upstream.

Vulkan-Tools — update 1.4.341.0 → 1.4.350.1.

• Drop the dead -DGLSLANG_INSTALL_DIR: upstream reads it from $ENV, not the
  CMake cache; the -D was a no-op emitting a warning.
• Drop libxkbcommon-devel and zeux-volk (stale makedepends).

Vulkan-Utility-Libraries — update 1.4.341.0 → 1.4.350.1.

• Add depends=Vulkan-Headers: every public header includes
  <vulkan/vulkan.h> unconditionally and the installed CMake config has no
  find_dependency, so nothing covers this automatically.

Vulkan-ValidationLayers — update 1.4.341.0 → 1.4.350.1.

• Add -DUPDATE_DEPS=OFF to resolve dependencies from the repo instead of
  fetching from the network mid-build.
• Drop glslang-devel (GPU-AV uses offline-compiled SPIR-V) and
  robin-hood-hashing (upstream vendors parallel_hashmap) from makedepends.

robin-hood-hashing — removed. Vulkan-ValidationLayers was the last consumer
and now uses the vendored parallel_hashmap. Upstream is discontinued, so it's
moved to removed-packages (robin-hood-hashing<=3.11.5_1) rather than kept.

The update files for the packages above were migrated to the refs/tags
(info/refs) pattern alongside each bump. Migration of packages outside this
stack goes in a separate PR.

This bump targets what we have available today. I'll likely follow up with a few
more Vulkan tools in separate PRs to round out the SDK for developers.

[Rutpiv]

Applied ($|(?=^)) to all update patterns. Rebased on master, removed-packages conflicted on the version date (another removal bumped it), kept the newer date. No other changes.