Fix ARM64 emulation support in all entrypoints (#587)

* Fix ARM64 emulation support in all entrypoints

- Add shared setup-exec.sh script to handle ARM64 emulation logic
- Update scenario.sh and scenario2map.sh to use box64 emulation on ARM64
- Refactor docker-entrypoint.sh and docker-entrypoint-rootless.sh to use shared script
- Ensures all factorio binary calls work correctly on ARM64 platforms

Fixes #585

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

Co-Authored-By: Claude <noreply@anthropic.com>

* Fix shellcheck warnings in entrypoint scripts

- Add shellcheck disable=SC1091 for dynamic source paths
- Quote INSTALLED_DIRECTORY variables to prevent word splitting
- Resolves all reported shellcheck issues in PR review

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

Co-Authored-By: Claude <noreply@anthropic.com>

* Add DLC handling to scenario.sh entrypoint

The docker-dlc.sh script was only called in docker-entrypoint.sh,
not in scenario.sh. This caused DLC_SPACE_AGE=false to not be
applied when using the scenario entrypoint, breaking it for users
without the Space Age DLC.

---------

Co-authored-by: Claude <noreply@anthropic.com>

docker/files/docker-entrypoint-rootless.sh

@@ -53,10 +53,9 @@ fi
 # In rootless mode, we don't need to handle user switching or chown
 # The container runs as the specified user from the start
 EXEC=""
-if [[ -f /bin/box64 ]]; then
-  # Use emulator for ARM hosts
-  EXEC="/bin/box64"
-fi
+# Setup ARM64 emulation support
+# shellcheck disable=SC1091
+source "${INSTALLED_DIRECTORY}/setup-exec.sh"
 
 # Update config path
 sed -i '/write-data=/c\write-data=\/factorio/' /opt/factorio/config/config.ini

docker/files/docker-entrypoint.sh

@@ -41,10 +41,10 @@ if [[ $NRTMPSAVES -gt 0 ]]; then
 fi
 
 if [[ ${UPDATE_MODS_ON_START:-} == "true" ]]; then
-  ${INSTALLED_DIRECTORY}/docker-update-mods.sh
+  "${INSTALLED_DIRECTORY}"/docker-update-mods.sh
 fi
 
-${INSTALLED_DIRECTORY}/docker-dlc.sh
+"${INSTALLED_DIRECTORY}"/docker-dlc.sh
 
 EXEC=""
 if [[ $(id -u) == 0 ]]; then
@@ -56,11 +56,10 @@ if [[ $(id -u) == 0 ]]; then
   # Drop to the factorio user
   EXEC="runuser -u factorio -g factorio --"
 fi
-if [[ -f /bin/box64 ]]; then
-  # Use an emulator to run on ARM hosts
-  # this only gets installed when the target docker platform is linux/arm64
-  EXEC="$EXEC /bin/box64"
-fi
+
+# Setup ARM64 emulation support
+# shellcheck disable=SC1091
+source "${INSTALLED_DIRECTORY}/setup-exec.sh"
 
 sed -i '/write-data=/c\write-data=\/factorio/' /opt/factorio/config/config.ini
 

docker/files/scenario.sh

@@ -1,5 +1,6 @@
 #!/bin/bash
 set -eoux pipefail
+INSTALLED_DIRECTORY=$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")
 
 if [[ -z ${1:-} ]]; then
   echo "No argument supplied"
@@ -31,7 +32,14 @@ if [[ ! -f $CONFIG/map-settings.json ]]; then
   cp /opt/factorio/data/map-settings.example.json "$CONFIG/map-settings.json"
 fi
 
-exec /opt/factorio/bin/x64/factorio \
+"${INSTALLED_DIRECTORY}"/docker-dlc.sh
+
+# Setup ARM64 emulation support
+EXEC=""
+# shellcheck disable=SC1091
+source "${INSTALLED_DIRECTORY}/setup-exec.sh"
+
+exec $EXEC /opt/factorio/bin/x64/factorio \
   --port "$PORT" \
   --start-server-load-scenario "$SERVER_SCENARIO" \
   --preset "$PRESET" \

docker/files/scenario2map.sh

@@ -1,5 +1,6 @@
 #!/bin/bash
 set -eoux pipefail
+INSTALLED_DIRECTORY=$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")
 
 if [[ -z ${1:-} ]]; then
   echo "No argument supplied"
@@ -23,5 +24,10 @@ if [[ ! -f $CONFIG/map-settings.json ]]; then
   cp /opt/factorio/data/map-settings.example.json "$CONFIG/map-settings.json"
 fi
 
-exec /opt/factorio/bin/x64/factorio \
+# Setup ARM64 emulation support
+EXEC=""
+# shellcheck disable=SC1091
+source "${INSTALLED_DIRECTORY}/setup-exec.sh"
+
+exec $EXEC /opt/factorio/bin/x64/factorio \
   --scenario2map "$SERVER_SCENARIO"

docker/files/setup-exec.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+# Setup EXEC variable for running Factorio with ARM64 emulation support
+# This script handles ARM64 emulation and can be combined with user switching as needed
+
+# If EXEC is not already set, initialize it
+if [[ -z "${EXEC:-}" ]]; then
+  EXEC=""
+fi
+
+if [[ -f /bin/box64 ]]; then
+  # Use an emulator to run on ARM hosts
+  # this only gets installed when the target docker platform is linux/arm64
+  EXEC="$EXEC /bin/box64"
+fi
+
+export EXEC