Repository-only release after v0.1.2.

• Adds the GitHub Copilot, LLM features, and secure-code courses in English and Chinese.
• Adds the seventh first-agent foundation module.
• Aligns all seven tool-course lessons with the explicit --attest flow.
• Completes the remaining L01 bilingual-parity fixes and refreshes the generated content manifest.

See CHANGELOG.md for the complete release record.