Python: [BREAKING] Python: Provider-leading client design & OpenAI package extraction (#4818)

* Python: Provider-leading client design & OpenAI package extraction

Major refactoring of the Python Agent Framework client architecture:

- Extract OpenAI clients into new `agent-framework-openai` package
- Core package no longer depends on openai, azure-identity, azure-ai-projects
- Rename clients for discoverability: OpenAIResponsesClient → OpenAIChatClient,
  OpenAIChatClient → OpenAIChatCompletionClient
- Unify `model_id`/`deployment_name`/`model_deployment_name` → `model` param
- New FoundryChatClient for Azure AI Foundry Responses API
- New FoundryAgent/FoundryAgentClient for connecting to pre-configured Foundry agents
- Remove OpenAIBase/OpenAIConfigMixin from non-deprecated client MRO
- Deprecate AzureOpenAI* clients, AzureAIClient, OpenAIAssistantsClient
- Reorganize samples: azure_openai+azure_ai+azure_ai_agent → azure/
- ADR-0020: Provider-Leading Client Design

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: missing Agent imports in samples, .model_id → .model in foundry_local sample

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: CI failures — mypy errors, coverage targets, sample imports

- azure-ai mypy: add type ignores for TypedDict total=, model arg, forward ref
- Coverage: replace core.azure/openai targets with openai package target
- project_provider: add type annotation for opts dict

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: populate openai .pyi stub, fix broken README links, coverage targets

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fixes

* updated observabilitty

* reset azure init.pyi

* fix errors

* updated adr number

* fix foundry local

* fixed not renamed docstrings and comments, and added deprecated markers to old classes

* fix tests and pyprojects

* fix test vars

* updated function tests

* update durable

* updated test setup for functions

* Fix Foundry auth in workflow samples

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Stabilize Python integration workflows

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Update hosting samples for Foundry

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Trigger full CI rerun

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Trigger CI rerun again

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* trigger rerun

* trigger rerun

* fix for litellm

* undo durabletask changes

* Move Foundry APIs into foundry namespace

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix Foundry pyproject formatting

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Split provider samples by Foundry surface

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Restore hosting sample requirements

Also fix the Foundry Local sample link after the provider sample move.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* updated tests

* udpated foundry integration tests

* removed dist from azurefunctions tests

* Use separate Foundry clients for concurrent agents

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix client setup in azfunc and durable

* disabled two tests

* updated setup for some function and durable tests

* improved azure openai setup with new clients

* ignore deprecated

* fixes

* skip 11

* remove openai assistants int tests

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

python/samples/01-get-started/06_host_your_agent.py

@@ -4,45 +4,37 @@
 # fmt: off
 from typing import Any
 
-from agent_framework.azure import AgentFunctionApp, AzureOpenAIChatClient
+from agent_framework import Agent
+from agent_framework.azure import AgentFunctionApp
+from agent_framework.foundry import FoundryChatClient
 from azure.identity import AzureCliCredential
-from dotenv import load_dotenv
-
-# Load environment variables from .env file
-load_dotenv()
 
 """Host your agent with Azure Functions.
-
 This sample shows the Python hosting pattern used in docs:
-- Create an agent with `AzureOpenAIChatClient`
+- Create an agent with `FoundryChatClient`
 - Register it with `AgentFunctionApp`
 - Run with Azure Functions Core Tools (`func start`)
-
 Prerequisites:
   pip install agent-framework-azurefunctions --pre
-
-Environment variables:
-  AZURE_OPENAI_ENDPOINT
-  AZURE_OPENAI_CHAT_DEPLOYMENT_NAME
 """
 
 
 # <create_agent>
 def _create_agent() -> Any:
     """Create a hosted agent backed by Azure OpenAI."""
-    return AzureOpenAIChatClient(credential=AzureCliCredential()).as_agent(
+    return Agent(
+        client=FoundryChatClient(
+            project_endpoint="https://your-project.services.ai.azure.com",
+            model="gpt-4o",
+            credential=AzureCliCredential(),
+        ),
         name="HostedAgent",
         instructions="You are a helpful assistant hosted in Azure Functions.",
     )
-
-
 # </create_agent>
-
 # <host_agent>
 app = AgentFunctionApp(agents=[_create_agent()], enable_health_check=True, max_poll_retries=50)
 # </host_agent>
-
-
 if __name__ == "__main__":
     print("Start the Functions host with: func start")
     print("Then call: POST /api/agents/HostedAgent/run")