refactor(core): refactor toolkit and skillBox registration

[fang-tech]

AgentScope-Java Version

1.0.4

Description

Refactor toolkit and skillBox registration
Now, for the situation where multiple tools are registered simultaneously, an error occurs when apply().
Passing in an empty value is no longer regarded as a valid call.

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 refactors the toolkit and skillBox registration mechanism to improve validation handling. The key change moves validation logic from individual setter methods to the apply() method using a counter-based approach, allowing multiple tool types to be set before validation occurs at application time.

• Introduces a toolCount counter in Toolkit.ToolRegistration to track the number of non-null tool types set
• Defers validation to the apply() method instead of checking immediately in each setter
• Simplifies SkillBox registration by delegating validation to Toolkit

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
agentscope-core/src/main/java/io/agentscope/core/tool/Toolkit.java	Refactored validation logic from setter methods to apply() using toolCount counter; removed immediate validation checks from tool(), agentTool(), mcpClient(), and subAgent() methods
agentscope-core/src/main/java/io/agentscope/core/skill/SkillBox.java	Simplified apply() method to pass all tool types to toolkit registration; updated error message
agentscope-core/src/test/java/io/agentscope/core/tool/ToolkitTest.java	Added comprehensive tests for multiple tool type validation and empty registration scenarios
agentscope-core/src/test/java/io/agentscope/core/skill/SkillBoxTest.java	Removed redundant tests that are now covered by ToolkitTest since validation moved to Toolkit

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[fang-tech]

CI failed reason is not related to this PR

[codecov]

Codecov Report

❌ Patch coverage is 90.90909% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...c/main/java/io/agentscope/core/skill/SkillBox.java	84.61%	1 Missing and 1 partial ⚠️

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