[Bug]: .openhands/setup.sh from repository not working

Is there an existing issue for the same bug?

• I have searched existing issues and this is not a duplicate.

Bug Description

When checking out a branch from a repo, the agent should automatically run .openhands/setup.sh, but this is currently broken.

Expected Behavior

.openhands/setup.sh should run as documented here: https://docs.openhands.dev/openhands/usage/customization/repository#setup-script
For the example below, a file called somefile.txt should be created.

Actual Behavior

The script is not executed. The script under "steps to reproduce" does not create a file somefile.txt.

Steps to Reproduce

Make a repo with an .openhands/setup.sh, e.g. with the content:

#!/bin/bash
touch somefile.txt

OpenHands Installation Method

Local GUI (Docker web interface)

If you selected "Other", please specify

No response

OpenHands Version

1.8.0

Version Confirmation

• I have confirmed this bug exists on the LATEST version of OpenHands

Model Name

No response

Operating System

No response

Browser (if using web UI)

No response

Logs and Error Messages

No response

Screenshots and Additional Context

Look at this code in openhands/app_server/app_conversation/app_conversation_service_base.py from maybe_run_setup_script:

        await workspace.execute_command(
            f'chmod +x {setup_script} && source {setup_script}',
            cwd=project_dir,
            timeout=600,
        )

source is a command that only exists in bash, but this command is probably executed in sh.
Not sure if there is any way to let the setup script export environment variables which would also be available for the agent. Would certainly be nice.
The docs (https://docs.openhands.dev/openhands/usage/customization/repository#setup-script) suggest that you can change the current directory in the script, which would have an effect for the agent. That's very similar to sharing environment variables, since both depend on the shell interpreter.

I tested a partial fix by changing:
f'chmod +x {setup_script} && source {setup_script}', to f'chmod +x {setup_script} && . {setup_script}',. That works, but current dir and environment variables wouldn't be shared. Still, better than before.

Start in openhands/app_server/app_conversation/app_conversation_service_base.py at maybe_run_setup_script, then inspect how workspace.execute_command invokes the command. Reproduce the documented .openhands/setup.sh example and verify that it executes successfully and creates somefile.txt; consider the reported current-directory and environment-variable behavior separately.