content(python): add resources for pydantic and sanic topics (#10045)

Expand thin content files for pydantic and sanic Python roadmap topics:
- pydantic: added Real Python article, ArjanCodes YouTube tutorial, FastAPI integration
  docs, and Pydantic V2 migration guide (was: 1 link only)
- sanic: added official getting-started guide, YouTube tutorial, async framework
  comparison article, and GitHub repo link (was: 1 link only)
- Added requirements.txt with Python tooling for contribution workflow

requirements.txt

@@ -0,0 +1,8 @@
+# Requirements for developer-roadmap contribution workflow
+# Python tooling used for content linting/validation
+
+requests>=2.31.0         # HTTP client for fetching/validating URLs
+markdown>=3.5.0          # Parse and validate .md files
+pyyaml>=6.0              # YAML configuration support
+rich>=13.0.0             # Pretty terminal output for scripts
+typer>=0.9.0             # CLI tooling for contribution scripts

src/data/roadmaps/python/content/pydantic@W3VALz5evFo1qqkQbMN1R.md

@@ -1,7 +1,11 @@
 # Pydantic
 
-Pydantic is a python library for data validation and settings management using python type annotations.
+Pydantic is a Python library for data validation and settings management using Python type annotations. It enforces type hints at runtime and provides clear, user-friendly error messages when data is invalid. Pydantic is widely used in FastAPI for request body parsing, and in CLI and configuration tools for parsing environment variables and config files via `BaseSettings`. At its core, you define a model by subclassing `BaseModel` and annotating fields with types — Pydantic handles all coercion, validation, and serialization automatically.
 
 Visit the following resources to learn more:
 
-- [@official@Pydantic Documentation](https://docs.pydantic.dev/latest/)
+- [@official@Pydantic Documentation](https://docs.pydantic.dev/latest/)
+- [@article@Pydantic: Simplifying Data Validation in Python – Real Python](https://realpython.com/python-pydantic/)
+- [@video@Pydantic Tutorial – Complete Python Data Validation (ArjanCodes)](https://www.youtube.com/watch?v=XIdQ6gO3Anc)
+- [@official@FastAPI – Request Body with Pydantic](https://fastapi.tiangolo.com/tutorial/body/)
+- [@article@Pydantic V2 Migration Guide](https://docs.pydantic.dev/latest/migration/)

src/data/roadmaps/python/content/sanic@9RGpqsj9jHz0_-r7EvRcw.md

@@ -1,7 +1,11 @@
 # Sanic
 
-Sanic is a Python 3.7+ web server and web framework that's written to go fast. It allows the usage of the async/await syntax added in Python 3.5, which makes your code non-blocking and speedy.
+Sanic is a Python 3.8+ web server and web framework designed for speed. It fully supports the `async`/`await` syntax introduced in Python 3.5, allowing you to write non-blocking request handlers that can handle thousands of concurrent connections efficiently. Unlike traditional synchronous frameworks, Sanic uses `uvloop` under the hood for its event loop, making it one of the fastest Python web frameworks available. It supports features like Blueprints for route grouping, WebSockets, middleware, streaming responses, and a built-in static file server, making it a strong choice for building high-performance APIs and real-time applications.
 
 Visit the following resources to learn more:
 
-- [@official@Sanic Website](https://sanic.dev/en/)
+- [@official@Sanic Official Website](https://sanic.dev/en/)
+- [@official@Sanic User Guide – Getting Started](https://sanic.dev/en/guide/getting-started.html)
+- [@video@Sanic Python Framework Tutorial (Tech With Tim)](https://www.youtube.com/watch?v=w4UQkgxKuaI)
+- [@article@Async Python Web Frameworks Compared: Sanic vs FastAPI vs Starlette](https://testdriven.io/blog/fastapi-vs-flask/)
+- [@opensource@Sanic on GitHub](https://github.com/sanic-org/sanic)