fix(harness): avoid duplicating GracefulShutdownMiddleware in fromAgent

[zouyx]

AgentScope-Java Version

2.0.0-SNAPSHOT

Description

This PR fixes #1950.

Background:
When HarnessAgent.Builder.fromAgent(ReActAgent) is used to wrap an existing ReActAgent, the source agent's middleware chain currently gets copied into the harness builder. Since ReActAgent always adds a system-level GracefulShutdownMiddleware during construction, copying that middleware causes the final harness delegate to contain two GracefulShutdownMiddleware instances.

Purpose:
Ensure GracefulShutdownMiddleware appears exactly once after cloning a ReActAgent into a HarnessAgent.

Changes made:

• Updated HarnessAgent.Builder.filterCopyableMiddlewares(...) to exclude GracefulShutdownMiddleware
• Added a regression assertion in HarnessAgentTest to verify the cloned delegate contains exactly one GracefulShutdownMiddleware

How to test:

• Run mvn -T1 -pl agentscope-harness -am -Dtest=HarnessAgentTest test
• Confirm fromAgent_filtersRuntimeMiddlewareAndStillPropagatesUserMiddleware passes and the cloned delegate keeps only one GracefulShutdownMiddleware

Checklist

Please check the following items before code is ready to be reviewed.

• Code has been formatted with mvn spotless:apply
• All tests are passing (mvn test)
• Javadoc comments are complete and follow project conventions
• Related documentation has been updated (e.g. links, examples, etc.)
• Code is ready for review

[Copilot]

Pull request overview

This PR fixes issue #1950 by preventing GracefulShutdownMiddleware from being duplicated when cloning a ReActAgent into a HarnessAgent via HarnessAgent.Builder.fromAgent(...). It ensures the cloned delegate ends up with exactly one system-level graceful-shutdown middleware while still propagating user-provided middleware.

Changes:

• Exclude GracefulShutdownMiddleware from the middleware list copied from the source agent during fromAgent(...).
• Add a regression assertion to verify the cloned delegate contains exactly one GracefulShutdownMiddleware.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
agentscope-harness/src/main/java/io/agentscope/harness/agent/HarnessAgent.java	Filters out GracefulShutdownMiddleware from copyable middlewares during fromAgent(...) cloning.
agentscope-harness/src/test/java/io/agentscope/harness/agent/HarnessAgentTest.java	Adds regression coverage asserting the cloned delegate has exactly one GracefulShutdownMiddleware.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...java/io/agentscope/harness/agent/HarnessAgent.java	0.00%	0 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

[zouyx]

• codecov/patch

I think it doesn't matter.

Because if i don't change this line, there is two GracefulShutdownMiddleware in child.getDelegate().getMiddlewares() .