fix: make Docker images backward compatible with runAsUser: 1000 (#8106)

## Summary
- Remove `--chown=65532:65532` from non-FIPS Dockerfile builds to
restore backward compatibility with helm charts using `runAsUser: 1000`
- Files are made world-readable via `chmod -R a+rX`
- FIPS/DHI builds still get proper 65532 ownership via `NONROOT_CHOWN`
build arg

## Test plan
- [ ] Gateway starts with `runAsUser: 1000` (old helm default)
- [ ] Gateway starts with `runAsUser: 65532`
- [ ] FIPS image still has proper nonroot ownership

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: buger

.github/workflows/release.yml

@@ -230,6 +230,7 @@ jobs:
           labels: ${{ steps.ci_metadata_fips.outputs.labels }}
           build-args: |
             BUILD_PACKAGE_NAME=tyk-gateway-fips
+            NONROOT_CHOWN=true
       - name: Docker metadata for fips tag push
         id: tag_metadata_fips
         uses: docker/metadata-action@v5
@@ -263,6 +264,7 @@ jobs:
           labels: ${{ steps.tag_metadata_fips.outputs.labels }}
           build-args: |
             BUILD_PACKAGE_NAME=tyk-gateway-fips
+            NONROOT_CHOWN=true
       - name: Docker metadata for std CI
         id: ci_metadata_std
         if: ${{ matrix.golang_cross == '1.25-bullseye' }}

ci/Dockerfile.distroless

@@ -10,11 +10,14 @@ ENV DEBIAN_FRONTEND=noninteractive
 
 # The _ after the pkg name is to match tyk-gateway strictly and not tyk-gateway-fips (for example)
 COPY ${BUILD_PACKAGE_NAME}_*${TARGETARCH}.deb /
-RUN dpkg -i /${BUILD_PACKAGE_NAME}_*${TARGETARCH}.deb && rm /*.deb
+ARG NONROOT_CHOWN=false
+RUN dpkg -i /${BUILD_PACKAGE_NAME}_*${TARGETARCH}.deb && rm /*.deb \
+    && chmod -R a+rX /opt/tyk-gateway/ \
+    && if [ "$NONROOT_CHOWN" = "true" ]; then chown -R 65532:65532 /opt/tyk-gateway/; fi
 
 FROM ${BASE_IMAGE}
 
-COPY --chown=65532:65532 --from=deb /opt/tyk-gateway /opt/tyk-gateway
+COPY --from=deb /opt/tyk-gateway /opt/tyk-gateway
 
 ARG PORTS
 EXPOSE $PORTS