client: Dockerfiles: local: root: use evergreencrypto/root image

- Provides C++20 support and a slimmer package (~18% smaller)
- Required for issue #23 (bitcoin-core lib support)

client/Dockerfiles/local/finance/archlinux/Dockerfile.root.in

@@ -1,6 +1,6 @@
 # docker-finance | modern accounting for the power-user
 #
-# Copyright (C) 2021-2024 Aaron Fiore (Founder, Evergreen Crypto LLC)
+# Copyright (C) 2021-2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -22,9 +22,12 @@
 USER root
 
 # ROOT.cern
-RUN pacman -Syu \
-  root \
-  --noconfirm --disable-download-timeout
+# https://hub.docker.com/r/evergreencrypto/root
+COPY --from=evergreencrypto/root:archlinux /home/builder/root/root-6.36.04-6-x86_64.pkg.tar.zst /usr/local/src/
+
+WORKDIR /usr/local/src
+RUN pacman -Syu --noconfirm --disable-download-timeout
+RUN pacman -U root-6.36.04-6-x86_64.pkg.tar.zst --noconfirm --disable-download-timeout
 
 # docker-finance
 RUN pacman -Syu \