- Enable Linux artifact building without requiring a local Linux environment (e.g., WSL or native Ubuntu)

- Designed to be executed via the 'linux-release-docker' command in the Makefile

Dockerfile

@@ -0,0 +1,34 @@
+
+# ==============================================================
+#  ⚠️  USAGE: TRIGGERED BY MAKEFILE
+#  This file is executed via the 'linux-release-docker' command.
+# ==============================================================
+
+FROM ubuntu:22.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+COPY linux_deps.list /tmp/linux_deps.list
+
+RUN apt-get update && \
+    DEPS=$(cat /tmp/linux_deps.list | tr -d '\r' | sed 's/#.*//g' | xargs) && \
+    \
+    apt-get install -y --no-install-recommends $DEPS && \
+    \
+    rm -rf /var/lib/apt/lists/* && \
+    echo "root ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers
+
+RUN wget -O /usr/local/bin/appimagetool "https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-x86_64.AppImage" && \
+    chmod +x /usr/local/bin/appimagetool
+
+RUN mkdir -p /root/develop && \
+    git clone https://github.com/flutter/flutter.git -b stable /root/develop/flutter
+
+ENV PATH="/root/develop/flutter/bin:/root/.pub-cache/bin:${PATH}"
+
+RUN git config --global --add safe.directory /root/develop/flutter && \
+    flutter config --no-analytics && \
+    dart pub global activate fastforge
+
+ENV APPIMAGE_EXTRACT_AND_RUN=1
+WORKDIR /app