feat: add Kotlin coroutine extension layer (Mono -> suspend, Flux -> Flow)

[shlokmestry]

AgentScope-Java Version

1.0.4-SNAPSHOT

Description

This PR adds a Kotlin coroutine extension layer for AgentScope Java to improve the Kotlin developer experience while keeping Reactor as the core async implementation.

A new optional module agentscope-kotlin is introduced under agentscope-extensions, providing Kotlin-friendly APIs on top of existing Reactor-based methods:

• Mono<Msg> → suspend fun
• Flux<Event> → Flow<Event>
• Mono<Void> → suspend fun returning Unit

All extensions are implemented as Kotlin extension functions, so no existing Java APIs or behaviors are changed.

What’s Included

• New agentscope-kotlin extension module
• Coroutine wrappers for Agent.call(...), Agent.observe(...), and Agent.stream(...)
• Uses kotlinx-coroutines-reactor for non-blocking interoperability
• No changes to core modules or Java implementations

Example Usage

val response = agent.callSuspend(msg)

agent.streamFlow(msg).collect { event ->
    println(event)
}

##How to test:

mvn -pl agentscope-extensions/agentscope-kotlin -am test

[shlokmestry]

The remaining failure appears to be in agentscope-extensions-a2a-client, which is unrelated to this PR.

[AlbumenJ]

Please revert these changes

[AlbumenJ]

Version should be managed in agentscope-dependencies-bom

[AlbumenJ]

Suggested change

	<artifactId>agentscope-kotlin</artifactId>
	<artifactId>agentscope-extensions-kotlin</artifactId>