ci: Refactor Windows CI into script

This makes it easier to:

* Run the exact command of any CI type and step locally
* Re-Run older CI tasks on GHA and using the latest merged config.
  (.github/ci-windows.py is merged with master on re-runs, but
  .github/workflows/ci.yml is NOT)

Also, writing it in Python has benefits:

* Any developer (even non-Windows ones) can read and modify the script.
* Python is already required for tests, so no new dependency is needed.

.github/ci-windows.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+# Copyright (c) The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+import argparse
+import os
+import shlex
+import subprocess
+import sys
+
+
+def run(cmd, **kwargs):
+    print("+ " + shlex.join(cmd), flush=True)
+    kwargs.setdefault("check", True)
+    try:
+        return subprocess.run(cmd, **kwargs)
+    except Exception as e:
+        sys.exit(str(e))
+
+
+GENERATE_OPTIONS = {
+    "standard": [
+        "-DBUILD_BENCH=ON",
+        "-DBUILD_KERNEL_LIB=ON",
+        "-DBUILD_UTIL_CHAINSTATE=ON",
+        "-DCMAKE_COMPILE_WARNING_AS_ERROR=ON",
+    ],
+    "fuzz": [
+        "-DVCPKG_MANIFEST_NO_DEFAULT_FEATURES=ON",
+        "-DVCPKG_MANIFEST_FEATURES=wallet",
+        "-DBUILD_GUI=OFF",
+        "-DWITH_ZMQ=OFF",
+        "-DBUILD_FOR_FUZZING=ON",
+        "-DCMAKE_COMPILE_WARNING_AS_ERROR=ON",
+    ],
+}
+
+
+def generate(ci_type):
+    toolchain_file = os.path.join(
+        os.environ["VCPKG_INSTALLATION_ROOT"],
+        "scripts",
+        "buildsystems",
+        "vcpkg.cmake",
+    )
+    command = [
+        "cmake",
+        "-B",
+        "build",
+        "-Werror=dev",
+        "--preset",
+        "vs2022",
+        f"-DCMAKE_TOOLCHAIN_FILE={toolchain_file}",
+    ] + GENERATE_OPTIONS[ci_type]
+    run(command)
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Utility to run Windows CI steps.")
+    parser.add_argument("ci_type", choices=GENERATE_OPTIONS, help="CI type to run.")
+    steps = ["generate"]
+    parser.add_argument("step", choices=steps, help="CI step to perform.")
+    args = parser.parse_args()
+
+    if args.step == "generate":
+        generate(args.ci_type)
+
+
+if __name__ == "__main__":
+    main()

.github/workflows/ci.yml

@@ -218,10 +218,8 @@ jobs:
         job-type: [standard, fuzz]
         include:
           - job-type: standard
-            generate-options: '-DBUILD_BENCH=ON -DBUILD_KERNEL_LIB=ON -DBUILD_UTIL_CHAINSTATE=ON -DCMAKE_COMPILE_WARNING_AS_ERROR=ON'
             job-name: 'Windows native, VS 2022'
           - job-type: fuzz
-            generate-options: '-DVCPKG_MANIFEST_NO_DEFAULT_FEATURES=ON -DVCPKG_MANIFEST_FEATURES="wallet" -DBUILD_GUI=OFF -DWITH_ZMQ=OFF -DBUILD_FOR_FUZZING=ON -DCMAKE_COMPILE_WARNING_AS_ERROR=ON'
             job-name: 'Windows native, fuzz, VS 2022'
 
     steps:
@@ -272,7 +270,7 @@ jobs:
 
       - name: Generate build system
         run: |
-          cmake -B build -Werror=dev --preset vs2022 -DCMAKE_TOOLCHAIN_FILE="${VCPKG_INSTALLATION_ROOT}/scripts/buildsystems/vcpkg.cmake" ${{ matrix.generate-options }}
+          py -3 .github/ci-windows.py ${{ matrix.job-type }} generate
 
       - name: Save vcpkg binary cache
         uses: actions/cache/save@v4