fix: remove WORKDIR necessities

Dockerfile

@@ -15,9 +15,10 @@ RUN sdkmanager \
         "build-tools;34.0.0" \
         "cmdline-tools;9.0" \
         "platform-tools" \
-        "platforms;android-33" \
-        "platforms;android-34" \
-        "platforms;android-35"
+        platforms\;android-{33..35}
+# https://gradle.org/releases/
+RUN curl -Lo /gradle.zip \
+    'https://services.gradle.org/distributions/gradle-8.12.1-bin.zip'
 
 FROM docker.io/debian:12-slim
 ENV DEBIAN_FRONTEND=noninteractive
@@ -29,9 +30,9 @@ RUN apt-get update \
         openjdk-17-jdk-headless \
         unzip \
     && rm -rf /var/lib/apt/lists/*
-RUN curl -Lo /gradle.zip \
-    'https://services.gradle.org/distributions/gradle-8.12.1-bin.zip'
 COPY --from=build /opt/ /opt/
+ENV GRADLE_ZIP=/gradle.zip
+COPY --from=build /gradle.zip "$GRADLE_ZIP"
 ENV PATH="/opt/flutter/bin:$PATH"
 RUN flutter config --android-sdk /opt/android-sdk/
 RUN flutter precache --android

entrypoint.sh

@@ -1,11 +1,12 @@
-#!/bin/bash -e
+#!/bin/bash
 
-cp -r . /app.tmp/
-cd /app.tmp/
-sed -i '/^distributionUrl/s =.\+ =file\\:///gradle.zip ' \
-    android/gradle/wrapper/gradle-wrapper.properties
+PROPS=android/gradle/wrapper/gradle-wrapper.properties
+BAK=/bak
+
+cp "$PROPS" "$BAK" || exit 1
+# shellcheck disable=SC2064
+trap "cp '$BAK' '$PROPS'" EXIT
+
+sed -i "/^distributionUrl/s =.\+ =file\\://$GRADLE_ZIP " "$PROPS"
 
 flutter --no-version-check "$@"
-
-cd -
-cp -r /app.tmp/build/ .