chore: optimize project metadata and documentation

[AIPMAndy]

Summary

This PR optimizes the CopyFlow project metadata and documentation to resolve inconsistencies and improve clarity.

Changes Made

1. LICENSE Alignment ✅

• Issue: LICENSE file specifies "PostSkill License 1.0.0" but pyproject.toml said "MIT" and README badge showed "Apache 2.0"
• Fix: Updated pyproject.toml license field to "PostSkill License 1.0.0" and corrected README badges

2. Brand Relationship Clarification ✅

• Issue: PostSkill mentioned in LICENSE but relationship to CopyFlow unclear
• Fix: Added dedicated LICENSE section in both README.md and README_EN.md explaining:
  • CopyFlow is a core component of the PostSkill content production toolchain
  • Key license highlights (free for personal/enterprise use, SaaS restrictions, brand retention requirements)
  • Link to full LICENSE file

3. Test Coverage Reporting ✅

• Issue: CI already uploads to Codecov but no badge in README
• Fix: Added codecov badge to both README.md and README_EN.md

4. More Examples ✅

• Issue: Only 1 example file existed (ai-awakening-output.md)
• Added 3 comprehensive examples:
  • ecommerce-product-launch.md - Smart bracelet product marketing (10 styles)
  • tech-tutorial-content.md - Python automation tutorial (10 styles)
  • b2b-saas-promotion.md - Team collaboration platform promotion (10 styles)

Each example demonstrates all 10 copy styles with realistic, production-ready content.

Files Changed

• README.md - Updated license badge and added LICENSE section
• README_EN.md - Updated license badge and added LICENSE section
• pyproject.toml - Changed license from "MIT" to "PostSkill License 1.0.0"
• examples/ecommerce-product-launch.md - New example (2.9KB)
• examples/tech-tutorial-content.md - New example (2.3KB)
• examples/b2b-saas-promotion.md - New example (2.6KB)

Testing

• Verified all links work correctly
• Confirmed codecov badge displays properly
• Reviewed all new example content for quality and consistency

Priority

Medium - Improves project clarity and provides better user guidance