ci: Add Windows + UCRT jobs for cross-compiling and native testing

Co-authored-by: will <will@256k1.dev>

ci/test/00_setup_env_win64.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2025-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+export LC_ALL=C.UTF-8
+
+export CONTAINER_NAME=ci_win64
+export CI_IMAGE_NAME_TAG="mirror.gcr.io/debian:trixie"  # Check that https://packages.debian.org/trixie/g++-mingw-w64-ucrt64 can cross-compile
+export HOST=x86_64-w64-mingw32ucrt
+export DEP_OPTS="CC=${HOST}-gcc CXX=${HOST}-g++"
+export PACKAGES="g++-mingw-w64-ucrt64 nsis"
+export RUN_UNIT_TESTS=false
+export RUN_FUNCTIONAL_TESTS=false
+export GOAL="deploy"
+export BITCOIN_CONFIG="\
+  --preset=dev-mode \
+  -DENABLE_IPC=OFF \
+  -DWITH_USDT=OFF \
+  -DREDUCE_EXPORTS=ON \
+  -DCMAKE_CXX_FLAGS='-Wno-error=maybe-uninitialized' \
+"