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/tools/control_total_tool_executions.py

@@ -3,7 +3,7 @@
 import asyncio
 from typing import Annotated
 
-from agent_framework import tool
+from agent_framework import Agent, tool
 from agent_framework.openai import OpenAIResponsesClient
 from dotenv import load_dotenv
 
@@ -88,7 +88,8 @@ async def scenario_max_iterations():
     client.function_invocation_configuration["max_iterations"] = 3
     print(f"  max_iterations = {client.function_invocation_configuration['max_iterations']}")
 
-    agent = client.as_agent(
+    agent = Agent(
+        client=client,
         name="ResearchAgent",
         instructions=(
             "You are a research assistant. Use the search_web tool to answer "
@@ -125,7 +126,8 @@ async def scenario_max_function_calls():
     print(f"  max_iterations    = {client.function_invocation_configuration['max_iterations']}")
     print(f"  max_function_calls = {client.function_invocation_configuration['max_function_calls']}")
 
-    agent = client.as_agent(
+    agent = Agent(
+        client=client,
         name="ResearchAgent",
         instructions=(
             "You are a research assistant. Use the search_web and get_weather "
@@ -155,7 +157,8 @@ async def scenario_max_invocations():
     print("Scenario 3: max_invocations — lifetime cap on a tool")
     print("=" * 60)
 
-    agent = OpenAIResponsesClient().as_agent(
+    agent = Agent(
+        client=OpenAIResponsesClient(),
         name="APIAgent",
         instructions="Use call_expensive_api when asked to analyze something.",
         tools=[call_expensive_api],
@@ -212,12 +215,14 @@ async def scenario_per_agent_tool_limits():
     agent_b_lookup = tool(name="lookup", approval_mode="never_require", max_invocations=5)(_do_lookup)
 
     client = OpenAIResponsesClient()
-    agent_a = client.as_agent(
+    agent_a = Agent(
+        client=client,
         name="AgentA",
         instructions="Use the lookup tool to answer questions.",
         tools=[agent_a_lookup],
     )
-    agent_b = client.as_agent(
+    agent_b = Agent(
+        client=client,
         name="AgentB",
         instructions="Use the lookup tool to answer questions.",
         tools=[agent_b_lookup],
@@ -270,7 +275,8 @@ async def scenario_combined():
 
     print(f"  premium_lookup.max_invocations = {premium_lookup.max_invocations}")
 
-    agent = client.as_agent(
+    agent = Agent(
+        client=client,
         name="MultiToolAgent",
         instructions="Use all available tools to answer comprehensively.",
         tools=[search_web, get_weather, premium_lookup],