Enhance README with comprehensive examples and structured documentation

[Copilot]

README.md Improvement - Complete ✓

All improvements completed:

• Fix grammar in description line
• Add badges section (PyPI, License, Python version)
• Add table of contents
• Add prerequisites/requirements section
• Improve installation instructions
• Add more comprehensive usage examples
• Add examples for all features (POS, NER, dependency parsing, word vectors)
• Add links to PyThaiNLP documentation
• Add contributing/support section
• Format configuration options in a more readable table format
• Improve overall structure and readability
• Remove duplicate configuration sections
• Add Resources section with links to documentation
• Run code review (passed with no issues)
• Run security checks (no code changes detected)
• Update Python version requirement to 3.9+ (per feedback)

Summary of changes:

• 176 additions, 33 deletions (net +143 lines)
• Improved documentation from 92 to 234 lines
• Added comprehensive examples for all 6 main features
• Better organization with table of contents
• Professional appearance with badges
• Clear installation and configuration instructions
• Updated Python requirement to 3.9+ in README and setup.py

Original prompt

Improve README.md

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[wannaphong]

@copilot Python 3.9+

[Copilot]

Updated to Python 3.9+ in both README.md and setup.py (commit 023d7b0)