fix(docs): standardize C4A-Script tutorial, add CLI identity-based crawling, and add sponsorship CTA

- Switch installs to pip install -r requirements.txt (tutorial and app docs)
- Update local run steps to python server.py and http://localhost:8000
- Set default PORT to 8000; update port-in-use commands and alt port 8001
- Replace unsupported :contains() example with accessible attribute selector
- Update example URLs in tutorial servers to 127.0.0.1:8000
- Add “Identity-based crawling” section with crwl profiles CLI workflow and code usage
- Replace legacy-docs note with sponsorship message in docs/md_v2/index.md
- Minor copy and consistency fixes across pages

docs/md_v2/index.md

@@ -57,7 +57,7 @@
 
 Crawl4AI is the #1 trending GitHub repository, actively maintained by a vibrant community. It delivers blazing-fast, AI-ready web crawling tailored for large language models, AI agents, and data pipelines. Fully open source, flexible, and built for real-time performance, **Crawl4AI** empowers developers with unmatched speed, precision, and deployment ease.
 
-> **Note**: If you're looking for the old documentation, you can access it [here](https://old.docs.crawl4ai.com).
+> Enjoy using Crawl4AI? Consider **[becoming a sponsor](https://github.com/sponsors/unclecode)** to support ongoing development and community growth!
 
 ## 🎯 New: Adaptive Web Crawling