Initialize git repo in Docker for webpack version detection

Create a git repo with tag so webpack git describe works

docker/Dockerfile

@@ -65,6 +65,14 @@ RUN apk add \
 WORKDIR ${SOURCE_DIR}
 COPY jellyfin-web .
 
+# Initialize git repo so webpack can get version info
+RUN git init \
+ && git config user.email "build@jellyfin.org" \
+ && git config user.name "Jellyfin Build" \
+ && git add -A \
+ && git commit -m "Build ${JELLYFIN_VERSION}" \
+ && git tag -a "v${JELLYFIN_VERSION}" -m "Version ${JELLYFIN_VERSION}"
+
 RUN npm ci --no-audit --unsafe-perm \
  && npm run build:production \
  && mv dist ${ARTIFACT_DIR}