fix: address PR review — Responses input encoding + finish Azure removal

- Replay prior-turn assistant text as input_text, not output_text: a
  Responses easy-input message only accepts input_* content parts, so the
  old shape would 400 on the second turn of every conversation (default
  store=false resends prior turns inline).
- Always request include=["reasoning.encrypted_content"] so in-turn
  reasoning carryover works whether or not the response is also stored
  server-side (OPENAI_RESPONSES_STORE).
- Add detail="auto" to input_image parts.
- Remove the now-dead azure_openai option from setup.sh / setup.ps1 and
  the docs, completing the AzureOpenAILLM removal.
- Tests: correct the input_text / image-detail / include assertions and
  add parallel tool-call and stream-error coverage.

docs/content/Models/cloud-providers.mdx

@@ -29,7 +29,6 @@ DocsGPT offers direct, streamlined support for the following cloud LLM providers
 | Anthropic (Claude)           | `anthropic`    | `claude-3-5-sonnet-20241022`|
 | Groq                         | `groq`         | `llama-3.3-70b-versatile`   |
 | HuggingFace Inference API    | `huggingface`  | `meta-llama/Llama-3.1-8B-Instruct` |
-| Azure OpenAI                 | `azure_openai` | `azure-gpt-4`               |
 | Prem AI                      | `premai`       | (See Prem AI docs)          |
 | AWS SageMaker                | `sagemaker`    | (See SageMaker docs)        |
 | Novita AI                    | `novita`       | (See Novita docs)           |