Enhance output schema documentation and validation in server.py

[Vikrant-Khedkar]

• Updated output schema examples to include a "required" field, ensuring clarity on its necessity.
• Added validation to automatically include a "required" field as an empty array if missing.
• Improved documentation for structured data extraction, emphasizing best practices and examples.

---

Note

Adds automatic required: [] normalization for output_schema, updates docs/examples to reflect it (and note URL-only mode), and improves startup logging.

• Server behavior:
  • Auto-normalizes output_schema by adding "required": [] when absent in smartscraper and agentic_scrapper.
  • Startup logs now indicate running from the local codebase with file path.
• Docs/UX:
  • Update output_schema examples and best practices to always include "required" (with notes that it’s auto-added if missing).
  • Clarify extraction tool docs (URL-only mode noted) and refine guidance/examples.

^{Written by Cursor Bugbot for commit 633f801. This will update automatically on new commits. Configure here.}