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/middleware/runtime_context_delegation.py

@@ -4,8 +4,8 @@ import asyncio
 from collections.abc import Awaitable, Callable
 from typing import Annotated
 
-from agent_framework import FunctionInvocationContext, function_middleware, tool
-from agent_framework.openai import OpenAIChatClient
+from agent_framework import Agent, FunctionInvocationContext, function_middleware, tool
+from agent_framework.foundry import FoundryChatClient
 from dotenv import load_dotenv
 from pydantic import Field
 
@@ -149,10 +149,11 @@ async def pattern_1_single_agent_with_closure() -> None:
     print("Use case: Single agent with multiple tools sharing runtime context")
     print()
 
-    client = OpenAIChatClient(model_id="gpt-4o-mini")
+    client = FoundryChatClient(model="gpt-4o-mini")
 
     # Create agent with both tools and shared context via middleware
-    communication_agent = client.as_agent(
+    communication_agent = Agent(
+        client=client,
         name="communication_agent",
         instructions=(
             "You are a communication assistant that can send emails and notifications. "
@@ -294,17 +295,19 @@ async def pattern_2_hierarchical_with_kwargs_propagation() -> None:
         print(f"[SMSAgent] Received runtime context: {list(context.kwargs.keys())}")
         await call_next()
 
-    client = OpenAIChatClient(model_id="gpt-4o-mini")
+    client = FoundryChatClient(model="gpt-4o-mini")
 
     # Create specialized sub-agents
-    email_agent = client.as_agent(
+    email_agent = Agent(
+        client=client,
         name="email_agent",
         instructions="You send emails using the send_email_v2 tool.",
         tools=[send_email_v2],
         middleware=[email_kwargs_tracker],
     )
 
-    sms_agent = client.as_agent(
+    sms_agent = Agent(
+        client=client,
         name="sms_agent",
         instructions="You send SMS messages using the send_sms tool.",
         tools=[send_sms],
@@ -312,7 +315,8 @@ async def pattern_2_hierarchical_with_kwargs_propagation() -> None:
     )
 
     # Create coordinator that delegates to sub-agents
-    coordinator = client.as_agent(
+    coordinator = Agent(
+        client=client,
         name="coordinator",
         instructions=(
             "You coordinate communication tasks. "
@@ -396,10 +400,11 @@ async def pattern_3_hierarchical_with_middleware() -> None:
 
     auth_middleware = AuthContextMiddleware()
 
-    client = OpenAIChatClient(model_id="gpt-4o-mini")
+    client = FoundryChatClient(model="gpt-4o-mini")
 
     # Sub-agent with validation middleware
-    protected_agent = client.as_agent(
+    protected_agent = Agent(
+        client=client,
         name="protected_agent",
         instructions="You perform protected operations that require authentication.",
         tools=[protected_operation],
@@ -407,7 +412,8 @@ async def pattern_3_hierarchical_with_middleware() -> None:
     )
 
     # Coordinator delegates to protected agent
-    coordinator = client.as_agent(
+    coordinator = Agent(
+        client=client,
         name="coordinator",
         instructions="You coordinate protected operations. Delegate to protected_executor.",
         tools=[