ci: build Windows with build_win.bat and drop the old scripts (#15721)

* ci: build Windows with build_win.bat and drop the old scripts

The deps and slicer jobs called build_release_vs.bat; they now call
build_win.bat. --deps-dir and --build-dir name the build/build-arm64
directories the cache keys and later steps already use, and the
script's own VsDevCmd call replaces the Enter-VsDevShell blocks.
With both stages configured each way into the same directory, the deps
superbuild is byte-identical and the slicer build files are
byte-identical apart from CMakeCache.txt recording how DEP_BUILD_DIR
was set.

Two changes beyond the script swap:

- The compiler is the clang-cl bundled with Visual Studio, the script's
  default. The old script's bare "clang-cl" resolved to the LLVM on the
  runner image's PATH, 20.1.8 on x64 and 22.1.8 on arm64; both arches
  now build with the 22.1.3 VS 18.9 ships. Cached dependencies are only
  rebuilt when deps/ changes, so they stay on the LLVM they were built
  with; the arm64 leg already links deps built with Clang 19 into a
  Clang 22 slicer.
- The deps job no longer zips the dependencies afterwards. The zip was
  never uploaded and was not in the cached path.

A failed cmake --build now fails the job. The old script returned 0, so
the arm64 failure fixed in #15719 was reported as success and the
half-built dependencies were saved to the cache.

build_release.bat, build_release_vs.bat and build_release_vs2022.bat are
removed; nothing referenced them any more.

* ci: run Build all when the Windows build script changes; tests doc builds the deps

The push filter of build_all.yml never listed a build script, and CI
now depends on build_win.bat, so it and its test suite join the list
the pull_request filter already has.

tests/AGENTS.md told Windows to run build_win.bat --run-tests, which
only implies -s and stops at the dependency check on a clean checkout.
The old build_release_vs.bat tests built the dependencies first, so
the line now says -ds --run-tests.

.github/workflows/build_orca.yml

@@ -450,21 +450,13 @@ jobs:
         # env:
         #   WindowsSdkDir: 'C:\Program Files (x86)\Windows Kits\10\'
         #   WindowsSDKVersion: '10.0.26100.0\'
-        # "tests" builds the unit tests too; the unit_tests_windows_* jobs run them.
+        # --tests builds the unit tests too; the unit_tests_windows_* jobs run them.
         run: |
-          $arch = "${{ inputs.arch }}"
-          # -l selects clang-cl and -x Ninja; together they build the slicer with clang.
-          $clang = "${{ inputs.compiler }}" -eq "clang"
-          $flags = if ($clang) { "-l", "-x" } else { @() }
-          if ($clang) {
-            # Build against the same VC toolchain and SDK as the dependencies.
-            $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
-            $vs = & $vswhere -latest -property installationPath
-            $devArch = if ($arch -eq "arm64") { "arm64" } else { "amd64" }
-            Import-Module "$vs\Common7\Tools\Microsoft.VisualStudio.DevShell.dll"
-            Enter-VsDevShell -VsInstallPath $vs -SkipAutomaticLocation -DevCmdArguments "-arch=$devArch"
-          }
-          if ($arch -eq "arm64") { .\build_release_vs.bat slicer arm64 @flags tests } else { .\build_release_vs.bat slicer @flags tests }
+          # cache-path is the install directory inside the deps build directory.
+          $deps = (Split-Path "${{ inputs.cache-path }}").Replace('\', '/')
+          # -l compiles with Visual Studio's clang-cl and -x builds with Ninja; --msvc --msbuild is cl under the Visual Studio generator.
+          $flags = if ("${{ inputs.compiler }}" -eq "clang") { "-l", "-x" } else { "--msvc", "--msbuild" }
+          .\build_win.bat -s --tests -i --arch ${{ inputs.arch }} --build-dir $env:BUILD_DIR --deps-dir $deps @flags
         shell: pwsh
 
       - name: Build system preset cache (Windows)