feat(ollama): Support Olama API key authentication

[laterya]

Summary

Adds support for Ollama Cloud integration in Spring AI by enabling API key-based authentication and allowing configuration of remote Ollama endpoints (e.g., https://ollama.com/api). This enables users to seamlessly use Ollama’s cloud-hosted large language models—such as gpt-oss:120b-cloud or qwen3-coder:480b-cloud—within Spring AI applications without requiring local GPU resources.

See Ollama Cloud documentation for details on available cloud models and authentication requirements.

Changes

• Added spring.ai.ollama.api-key configuration property
• Extended [OllamaConnectionDetails] interface with [getApiKey()] method (default null)
• Modified [OllamaApiAutoConfiguration] to inject Authorization: Bearer header when API key is present

Configuration Example

spring:
  ai:
    ollama:
      base-url: https://ollama.com/api
      api-key: ${OLLAMA_API_KEY}