ci: cross-compile Windows Bazel clippy

[bolinfest]

Why

#20585 moved the Windows Bazel test job to the cross-compile path, but the Windows Bazel clippy and verify-release-build jobs were still using the native Windows/MSVC-host fallback. Those two jobs became the slowest Windows PR legs, even though both are build-only signal and do not need to execute the resulting binaries.

What Changed

• Switches the Windows Bazel clippy job from --windows-msvc-host-platform to --windows-cross-compile, so clippy build actions use Linux RBE while still targeting x86_64-pc-windows-gnullvm.
• Switches the Windows Bazel verify-release-build job to --windows-cross-compile as well. This job only compiles cfg(not(debug_assertions)) Rust code under fastbuild, so it does not need a native Windows build host.
• Keeps the old --skip_incompatible_explicit_targets behavior only for fork/community PRs without BUILDBUDDY_API_KEY, where run-bazel-ci.sh falls back to the local Windows MSVC-host shape.
• Adds --windows-cross-compile support to .github/scripts/run-bazel-query-ci.sh, so target-discovery queries select the same ci-windows-cross config as the subsequent build.
• Threads that option through scripts/list-bazel-clippy-targets.sh so the Windows clippy job discovers targets under the same platform shape as the subsequent clippy build.

Verification

Local checks:

bash -n .github/scripts/run-bazel-query-ci.sh
bash -n scripts/list-bazel-clippy-targets.sh
ruby -e 'require "yaml"; YAML.load_file(".github/workflows/bazel.yml"); puts "ok"'
RUNNER_OS=Linux ./scripts/list-bazel-clippy-targets.sh | grep -c -- '-windows-cross-bin$'
RUNNER_OS=Windows ./scripts/list-bazel-clippy-targets.sh --windows-cross-compile | grep -c -- '-windows-cross-bin$'

The Linux target-list check reported 0 Windows-cross internal test binaries, while the Windows cross target-list check reported 47, preserving the test-code clippy coverage shape from the existing Windows job.