[User Story] - Add support for Langchain4j Agentic Module

[dantelmomsft]

Description Convert the supervisor, account, transaction, payment agents to use the recently released agentic module from langchain4j

Current Behavior The current agentic implementation is based on a custom react agent based on langchain4j low level API.

Acceptance Criteria

• [ ] No regression on account, transaction, payment flows.

Design Considerations

• Consider to use the pre-built supervisor orchestration. https://docs.langchain4j.dev/tutorials/agents#pure-agentic-ai.

Main Affected Modules and/or Classes -https://github.com/Azure-Samples/agent-openai-java-banking-assistant/blob/main/app/copilot/langchain4j-agents/src/main/java/com/microsoft/openai/samples/assistant/langchain4j/agent/SupervisorAgent.java

• https://github.com/Azure-Samples/agent-openai-java-banking-assistant/blob/main/app/copilot/langchain4j-agents/src/main/java/com/microsoft/openai/samples/assistant/langchain4j/agent/mcp/AccountMCPAgent.java
• https://github.com/Azure-Samples/agent-openai-java-banking-assistant/blob/main/app/copilot/langchain4j-agents/src/main/java/com/microsoft/openai/samples/assistant/langchain4j/agent/mcp/PaymentMCPAgent.java
• https://github.com/Azure-Samples/agent-openai-java-banking-assistant/blob/main/app/copilot/langchain4j-agents/src/main/java/com/microsoft/openai/samples/assistant/langchain4j/agent/mcp/TransactionHistoryMCPAgent.java

References [Link to docs, ADRs, samples, related issues. Example:

• Agent middleware docs: <URL>
• Sample middleware implementation: <URL>](https://docs.langchain4j.dev/tutorials/agents)