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/02-agents/devui/workflow_agents/workflow.py

@@ -17,8 +17,8 @@ Both paths converge at Summarizer for final report.
 import os
 from typing import Any
 
-from agent_framework import AgentExecutorResponse, WorkflowBuilder
-from agent_framework.azure import AzureOpenAIChatClient
+from agent_framework import Agent, AgentExecutorResponse, WorkflowBuilder
+from agent_framework.foundry import FoundryChatClient
 from dotenv import load_dotenv
 from pydantic import BaseModel
 
@@ -63,10 +63,11 @@ def is_approved(message: Any) -> bool:
 
 
 # Create Azure OpenAI chat client
-client = AzureOpenAIChatClient(api_key=os.environ.get("AZURE_OPENAI_API_KEY", ""))
+client = FoundryChatClient(api_key=os.environ.get("AZURE_OPENAI_API_KEY", ""))
 
 # Create Writer agent - generates content
-writer = client.as_agent(
+writer = Agent(
+    client=client,
     name="Writer",
     instructions=(
         "You are an excellent content writer. "
@@ -76,7 +77,8 @@ writer = client.as_agent(
 )
 
 # Create Reviewer agent - evaluates and provides structured feedback
-reviewer = client.as_agent(
+reviewer = Agent(
+    client=client,
     name="Reviewer",
     instructions=(
         "You are an expert content reviewer. "
@@ -94,7 +96,8 @@ reviewer = client.as_agent(
 )
 
 # Create Editor agent - improves content based on feedback
-editor = client.as_agent(
+editor = Agent(
+    client=client,
     name="Editor",
     instructions=(
         "You are a skilled editor. "
@@ -105,7 +108,8 @@ editor = client.as_agent(
 )
 
 # Create Publisher agent - formats content for publication
-publisher = client.as_agent(
+publisher = Agent(
+    client=client,
     name="Publisher",
     instructions=(
         "You are a publishing agent. "
@@ -115,7 +119,8 @@ publisher = client.as_agent(
 )
 
 # Create Summarizer agent - creates final publication report
-summarizer = client.as_agent(
+summarizer = Agent(
+    client=client,
     name="Summarizer",
     instructions=(
         "You are a summarizer agent. "