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- One superseded minimal_sample.py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/packages/durabletask/tests/integration_tests/conftest.py

@@ -382,7 +382,7 @@ def worker_process(
         pytest.fail("Test class must have @pytest.mark.sample() marker")
 
     sample_name: str = cast(str, sample_marker.args[0])  # type: ignore[union-attr]
-    sample_path: Path = Path(__file__).parents[4] / "samples" / "getting_started" / "durabletask" / sample_name
+    sample_path: Path = Path(__file__).parents[4] / "samples" / "04-hosting" / "durabletask" / sample_name
     worker_file: Path = sample_path / "worker.py"
 
     if not worker_file.exists():

python/packages/durabletask/tests/integration_tests/test_03_dt_single_agent_streaming.py

@@ -27,7 +27,7 @@ import pytest
 import redis.asyncio as aioredis
 
 # Add sample directory to path to import RedisStreamResponseHandler
-SAMPLE_DIR = Path(__file__).parents[4] / "samples" / "getting_started" / "durabletask" / "03_single_agent_streaming"
+SAMPLE_DIR = Path(__file__).parents[4] / "samples" / "04-hosting" / "durabletask" / "03_single_agent_streaming"
 sys.path.insert(0, str(SAMPLE_DIR))
 
 from redis_stream_response_handler import RedisStreamResponseHandler  # type: ignore[reportMissingImports] # noqa: E402