native-review: natural greetings & self-introduction for Lesson 01

[1977-code]

Lesson 01 (08_textbook/chapters/L01_DRAFT.md) currently has placeholder examples for greetings and self-introduction, pending native review.

Ask for native speakers / teachers: propose natural, everyday Abkhaz for:

• greeting someone and asking how they are
• introducing yourself (name, where you are from)
• a polite goodbye

Even one line is a real contribution. No coding needed — comment here or open a PR. See 05_methodology/NATIVE_REVIEW_GUIDE.md.