chore(build): add dockerfile for building

Dockerfile

@@ -0,0 +1,35 @@
+FROM img/android:2024.11.1
+
+WORKDIR sing-box-for-android
+
+USER root
+
+# Go environment
+ENV GOBIN='/home/circleci/go/bin'
+ENV GOPATH="/home/circleci/go"
+ENV PATH="$PATH:/usr/local/go/bin:/home/circleci/go/bin"
+
+# prepare jdk
+# prepare android ndk
+RUN apt install openjdk-17-jdk && \
+    update-alternatives --set java /usr/lib/jvm/java-17-openjdk-amd64/bin/java && \
+    update-alternatives --set javac /usr/lib/jvm/java-17-openjdk-amd64/bin/javac && \
+    update-alternatives --set javadoc /usr/lib/jvm/java-17-openjdk-amd64/bin/javadoc && \
+    sdkmanager --install "ndk;26.2.11394342"
+
+# download sing-box source code 
+RUN cd .. && \
+    wget https://codeload.github.com/SagerNet/sing-box/zip/refs/heads/main && \
+    unzip main && \
+    rm main && \
+    mv sing-box-main sing-box && \
+    wget https://go.dev/dl/go1.23.3.linux-amd64.tar.gz && \
+    tar -C /usr/local -xzf go1.23.3.linux-amd64.tar.gz && \
+    rm go1.23.3.linux-amd64.tar.gz 
+
+COPY . .
+
+RUN cd ../sing-box && \
+    make lib_install && \
+    make lib_android && \
+    make build_android