fix(harness): preserve Docker exec commands on Windows

[guslegend0510]

AgentScope-Java Version

2.0.3-SNAPSHOT

Description

Fixes #2924

DockerSandbox.doExec() previously passed the complete shell command as the final docker.exe argument (sh -c <command>). On Windows, nested double quotes can be altered while the Win32 command line is serialized and parsed, breaking filesystem commands such as write_file and edit_file.

This PR:

• runs docker exec -i ... sh -s and streams the command through UTF-8 stdin instead of placing it in argv;
• wraps the streamed command so command-level stdin remains isolated while heredocs and explicit redirections continue to work;
• preserves existing stdout/stderr capture, output truncation, non-zero exit, and timeout behavior;
• adds regression tests for nested quotes, Unicode, multiline heredocs, non-zero exits, timeouts, and output truncation.

Testing

• mvn -pl agentscope-harness -am -Dtest=DockerSandboxExecTest -Dsurefire.failIfNoSpecifiedTests=false test
• mvn -pl agentscope-harness -am test
• mvn spotless:check
• git diff --check
• Docker Linux-container verification covering the Issue [Bug]:DockerSandbox.doExec() strips nested double quotes on Windows #2924 reproduction, file write, Python heredoc edit, and stdin isolation

Checklist

• Code has been formatted with mvn spotless:apply
• All tests are passing (mvn test)
• Javadoc comments are complete and follow project conventions
• Related documentation is not required; the implementation Javadoc was updated
• Code is ready for review

[codecov]

Codecov Report

❌ Patch coverage is 85.29412% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...rness/agent/sandbox/impl/docker/DockerSandbox.java	85.29%	5 Missing ⚠️

📢 Thoughts on this report? Let us know!