Python: restructure: Python samples into progressive 01-05 layout (#3862)

* restructure: Python samples into progressive 01-05 layout

- 01-get-started/: 6 numbered steps (hello agent → hosting)
- 02-agents/: all agent concept samples (tools, middleware, providers, etc.)
- 03-workflows/: ALL existing workflow samples preserved as-is
- 04-hosting/: azure-functions, durabletask, a2a
- 05-end-to-end/: demos, evaluation, hosted agents
- Old files moved to _to_delete/ for review
- Added AGENTS.md with structure documentation
- autogen-migration/ and semantic-kernel-migration/ preserved at root

* fix: switch to AzureOpenAI Foundry, fix CI failures

- Switch all 01-get-started samples to AzureOpenAIResponsesClient with
  Azure AI Foundry project endpoint (AZURE_AI_PROJECT_ENDPOINT +
  AZURE_OPENAI_RESPONSES_DEPLOYMENT_NAME + AzureCliCredential)
- Add _to_delete/ and 05-end-to-end/ to pyrightconfig.samples.json excludes
- Fix test paths in packages/ that referenced old getting_started/ dirs:
  durabletask conftest + streaming test, azurefunctions conftest,
  devui conftest + capture_messages + openai_sdk_integration
- Fix workflow_as_agent_human_in_the_loop.py import (sibling import)
- Update hosting READMEs and tool comment paths
- Replace root README.md with new structure overview
- Update AGENTS.md to document Azure OpenAI Foundry as default provider

* cleanup: remove _to_delete folder, copy resource files to active dirs

All files in _to_delete/ were either:
- Exact duplicates of files in the new structure (240 files)
- Same file with only comment path updates (100 files)
- One import-fix diff (workflow_as_agent_human_in_the_loop.py)
- One superseded minimal_sample.py

Resource files (sample.pdf, countries.json, employees.pdf, weather.json)
copied to 02-agents/sample_assets/ and 02-agents/resources/ since active
samples reference them.

* fix: address PR review comments, centralize resources, remove root duplicates

- Fix type annotation in 04_memory.py (string union -> proper types)
- Fix old sample paths in observability files
- Fix grammar/spelling in observability samples
- Move sample_assets/ and resources/ to shared/ folder
- Remove 8 duplicate observability files from 02-agents root
- Update resource path references in multimodal_input and provider samples

* fix: update broken links from old getting_started paths to new structure

- Update relative paths in READMEs: getting_started/ → 01-get-started/,
  02-agents/, 03-workflows/, 04-hosting/, 05-end-to-end/
- Fix absolute GitHub URLs in package READMEs
- Fix broken link in ollama package README

* fix: convert absolute GitHub URLs to relative paths for link checker

Absolute URLs to python/samples/ on main branch 404 until PR merges.
Converted to relative paths that linkspector can verify locally.

* fix: update link for handoff sample moved to orchestrations/

* fix: update chatkit-integration README path from demos/ to 05-end-to-end/

* fix: update broken links in orchestrations README to match flat directory structure

python/samples/04-hosting/durabletask/02_multi_agent/sample.py

@@ -0,0 +1,58 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Multi-Agent Sample - Durable Task Integration (Combined Worker + Client)
+
+This sample demonstrates running both the worker and client in a single process
+for multiple agents with different tools. The worker registers two agents
+(WeatherAgent and MathAgent), each with their own specialized capabilities.
+
+Prerequisites:
+- Set AZURE_OPENAI_ENDPOINT and AZURE_OPENAI_CHAT_DEPLOYMENT_NAME
+  (plus AZURE_OPENAI_API_KEY or Azure CLI authentication)
+- Durable Task Scheduler must be running (e.g., using Docker)
+
+To run this sample:
+    python sample.py
+"""
+
+import logging
+
+# Import helper functions from worker and client modules
+from client import get_client, run_client
+from dotenv import load_dotenv
+from worker import get_worker, setup_worker
+
+# Configure logging
+logging.basicConfig(level=logging.INFO, force=True)
+logger = logging.getLogger(__name__)
+
+
+def main():
+    """Main entry point - runs both worker and client in single process."""
+    logger.debug("Starting Durable Task Multi-Agent Sample (Combined Worker + Client)...")
+
+    silent_handler = logging.NullHandler()
+    # Create and start the worker using helper function and context manager
+    with get_worker(log_handler=silent_handler) as dts_worker:
+        # Register agents using helper function
+        setup_worker(dts_worker)
+
+        # Start the worker
+        dts_worker.start()
+        logger.debug("Worker started and listening for requests...")
+
+        # Create the client using helper function
+        agent_client = get_client(log_handler=silent_handler)
+
+        try:
+            # Run client interactions using helper function
+            run_client(agent_client)
+        except Exception as e:
+            logger.exception(f"Error during agent interaction: {e}")
+
+        logger.debug("Sample completed. Worker shutting down...")
+
+
+if __name__ == "__main__":
+    load_dotenv()
+    main()