Python: replace pre-commit with prek, add PEP 723 script deps, clean up dev dependencies (#3748)

* python: replace pre-commit with prek, add PEP 723 script deps, clean up dev dependencies

- Replace pre-commit with prek (Rust-native, faster pre-commit alternative)
- Move supported hooks to repo: builtin for zero-clone speed
- Add new builtin hooks: trailing-whitespace, check-merge-conflict, detect-private-key, check-added-large-files
- Update all hook versions to latest (pre-commit-hooks v6, pyupgrade v3.21.2, bandit 1.9.3, uv-pre-commit 0.10.0)
- Add PEP 723 inline script metadata to 34 samples with external deps
- Remove autogen-agentchat/autogen-ext from dev deps (now declared per-sample)
- Remove unused dev deps: pytest-env, tomli-w
- Add agent-framework-core>=1.0.0b260130 lower bound to all 21 packages
- Update CI workflow to use j178/prek-action
- Update docs: DEV_SETUP.md, AGENTS.md, CODING_STANDARD.md, SAMPLE_GUIDELINES.md

* updated lock

* python: fix prek config paths for local execution and CI workflow

Remove global 'files: ^python/' filter and strip python/ prefix from all path patterns in .pre-commit-config.yaml so prek finds files when run from the python/ directory. Update CI workflow to use --cd python instead of --config path. Include trailing whitespace fixes and dev dependency cleanup.

* python: move helper scripts to scripts/ folder and exclude from checks

* python: exclude AGENTS.md from prek markdown code lint

* python: exclude AGENTS.md and azure_ai_search sample from markdown lint

* fix m365 sample

* python: ignore CPY rule for samples with PEP 723 headers

* fix in dev_setup

* python: replace aiofiles with regular open in samples

* python: suppress reportUnusedImport in markdown code block checker

* python: use samples pyright config for markdown code block checker

Write a temp pyrightconfig.json matching pyrightconfig.samples.json rules (typeCheckingMode=off, only reportMissingImports and reportAttributeAccessIssue). Filter output to only fail on these rules since syntax-level errors (top-level await, undefined vars) are expected in README documentation snippets.

* python: use markdown-code-lint with fixed globs instead of prek file list

The prek-markdown-code-lint task received all changed files including non-README markdown and files with pre-existing broken imports. Replace with the standard markdown-code-lint task which uses the correct glob patterns (README.md, packages/**/README.md, samples/**/*.md).

* python: exclude READMEs with pre-existing broken imports from markdown lint

* python: fix broken README code snippets instead of excluding them

- ag-ui: replace TextContent (removed) with content.type == 'text'
- durabletask: fix import path to durabletask.worker.TaskHubGrpcWorker
- orchestrations: use constructor params instead of .participants() method
- observability: mark deprecated code blocks as plain text, filter
  reportMissingImports to agent_framework modules only
- remove README excludes from markdown-code-lint task

* add revision to gaia download

* feat(python): parallelize checks across packages

Run (package × task) cross-product in parallel using ThreadPoolExecutor
and subprocesses. Key changes:

- Add scripts/task_runner.py with shared parallel execution engine
- Update run_tasks_in_packages_if_exists.py to accept multiple tasks
- Update run_tasks_in_changed_packages.py with --files flag and parallel support
- Add check-packages poe task (fmt+lint+pyright+mypy in parallel)
- Add prek-markdown-code-lint and prek-samples-check with change detection
- Split CI code quality workflow into parallel prek and mypy jobs
- Update DEV_SETUP.md to document new parallel behavior

Core package changes still trigger checks on all packages.

* feat(ci): split code quality into 4 parallel jobs

Split the single prek job into parallel jobs:
- pre-commit-hooks: lightweight hooks (SKIP=poe-check)
- package-checks: fmt/lint/pyright/mypy via check-packages
- samples-markdown: samples-lint, samples-syntax, markdown-code-lint
- mypy: change-detected mypy checks

All 4 jobs run concurrently (×2 Python versions = 8 runners).

* feat(ci): use only Python 3.10 for code quality checks

* refactor(python): add future annotations and remove quoted types

Add `from __future__ import annotations` to 93 package files that
used quoted string annotations, then run pyupgrade --py310-plus to
remove the now-unnecessary quotes.

Fixes https://github.com/microsoft/agent-framework/issues/3578

python/samples/SAMPLE_GUIDELINES.md

@@ -2,6 +2,45 @@
 
 Samples are extremely important for developers to get started with Agent Framework. We strive to provide a wide range of samples that demonstrate the capabilities of Agent Framework with consistency and quality. This document outlines the guidelines for creating samples.
 
+## File Structure
+
+Every sample file should follow this order:
+
+1. PEP 723 inline script metadata (if external dependencies are needed)
+2. Copyright header: `# Copyright (c) Microsoft. All rights reserved.`
+3. Required imports
+4. Module docstring: `"""This sample demonstrates..."""`
+5. Helper functions
+6. Main function(s) demonstrating functionality
+7. Entry point: `if __name__ == "__main__": asyncio.run(main())`
+
+When modifying samples, update associated README files in the same or parent folders.
+
+## External Dependencies
+
+When samples depend on external packages not included in the dev environment (e.g., `semantic-kernel`, `autogen-agentchat`, `pandas`), declare them using [PEP 723](https://peps.python.org/pep-0723/) inline script metadata at the top of the file, before the copyright header:
+
+```python
+# /// script
+# requires-python = ">=3.10"
+# dependencies = [
+#     "some-external-package",
+# ]
+# ///
+# Run with any PEP 723 compatible runner, e.g.:
+#   uv run samples/path/to/script.py
+
+# Copyright (c) Microsoft. All rights reserved.
+```
+
+This makes samples self-contained and runnable without installing extra packages into the dev environment. Do not add sample-only dependencies to the root `pyproject.toml` dev group.
+
+## Syntax Checking
+
+Run `uv run poe samples-syntax` to check samples for syntax errors and missing imports from `agent_framework`. This uses a relaxed pyright configuration that validates imports without strict type checking.
+
+Some samples depend on external packages (e.g., `azure.ai.agentserver.agentframework`, `microsoft_agents`) that are not installed in the dev environment. These are excluded in `pyrightconfig.samples.json`. When adding or modifying these excluded samples, add them to the exclude list and manually verify they have no import errors from `agent_framework` packages by temporarily removing them from the exclude list and running the check.
+
 ## General Guidelines
 
 - **Clear and Concise**: Samples should be clear and concise. They should demonstrate a specific set of features or capabilities of Agent Framework. The less concepts a sample demonstrates, the better.
@@ -49,7 +88,7 @@ For the getting started samples and the concept samples, we should have the foll
     ```python
     # 1. Create the instance of the Kernel to register the plugin and service.
     ...
-    
+
     # 2. Create the agent with the kernel instance.
     ...
     ```
@@ -64,7 +103,7 @@ For the getting started samples and the concept samples, we should have the foll
     User:> Why is the sky blue in one sentence?
     Mosscap:> The sky is blue due to the scattering of sunlight by the molecules in the Earth's atmosphere,
     a phenomenon known as Rayleigh scattering, which causes shorter blue wavelengths to become more
-    prominent in our visual perception.    
+    prominent in our visual perception.
     '''
     ```