feat(core): propagate ToolResultBlock metadata through agent events and AG-UI protocol

[ningmeng0503]

AgentScope-Java Version

2.0.1-SNAPSHOT

Description

Tools may return structured execution context via ToolResultBlock.metadata, but this metadata is currently dropped when converting tool results into events. This
PR propagates ToolResultBlock.getMetadata() end-to-end through the v2 agent event stream and the AG-UI protocol so consumers can access tool-specific context.

Changes made

• Core events (agentscope-core):

  • Added metadata support to ToolResultStartEvent, ToolResultTextDeltaEvent, ToolResultDataDeltaEvent, and ToolResultEndEvent.
  • Added backward-compatible constructors that delegate to the new @JsonCreator constructors with metadata = null.
  • Updated ReActAgent.runToolBatch to copy ToolResultBlock.metadata into delta and end events.

• AG-UI protocol (agentscope-extensions-agui):

  • Extended AguiEvent.ToolCallResult with a nullable metadata field.
  • Updated AguiAgentAdapter.convertEvent to populate ToolCallResult metadata from ToolResultBlock.

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 has been updated (e.g. links, examples, etc.)
• Code is ready for review

[codecov]

Codecov Report

❌ Patch coverage is 75.60976% with 10 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...e/src/main/java/io/agentscope/core/ReActAgent.java	72.72%	6 Missing ⚠️
...gentscope/core/event/ToolResultDataDeltaEvent.java	66.66%	1 Missing ⚠️
...a/io/agentscope/core/event/ToolResultEndEvent.java	66.66%	1 Missing ⚠️
...io/agentscope/core/event/ToolResultStartEvent.java	66.66%	1 Missing ⚠️
...gentscope/core/event/ToolResultTextDeltaEvent.java	66.66%	1 Missing ⚠️

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