[TASK] dotAI: LangChain4J - Azure OpenAI provider

[fmontes]

Description

Add Azure OpenAI as a supported provider in the dotAI LangChain4J integration layer (Phase 2 of multi-provider support). Enterprise customers using Azure-hosted OpenAI deployments need to configure dotAI without code changes — only a providerConfig JSON update should be required.

This builds on the LangChain4J abstraction established in #35183 (Phase 1 — OpenAI).

Implementation outline:

• Add langchain4j-azure-open-ai dependency
• Add azure_openai case to LangChain4jModelFactory switch
• Implement buildAzureOpenAiChatModel, buildAzureOpenAiEmbeddingModel, buildAzureOpenAiImageModel
• Pin Netty (4.1.118.Final) and Reactor (3.4.41) in BOM to resolve transitive version conflicts introduced by the Azure SDK

Acceptance Criteria

• azure_openai is selectable as a provider in providerConfig for chat, embeddings, and image sections
• deploymentName is required for Azure (falls back to model if not set)
• apiVersion maps to Azure's serviceVersion (recommended: 2024-02-01)
• Netty/Reactor version pins do not affect existing OpenAI behavior
• Unit tests cover Azure chat, embedding, and image model builders in LangChain4jModelFactoryTest
• No breaking changes to existing OpenAI configuration

Additional Context

• Parent: [FEATURE] dotAI: LangChain4J integration — Phase 1 (OpenAI) #35183 (Phase 1 - OpenAI)
• Epic: EPIC: dotAI Multi-Provider Support #33970 (dotAI Multi-Provider Support)
• Implementation PR: feat(dotAI): Dot AI LangChain4J - Azure OpenAI #35243

Sample configuration:

{
  "chat": {
    "provider": "azure_openai",
    "apiKey": "...",
    "endpoint": "https://my-company.openai.azure.com/",
    "deploymentName": "gpt-4o",
    "apiVersion": "2024-02-01",
    "maxTokens": 16384,
    "temperature": 1.0
  }
}