- Add gomarkdoc-driven reference docs in docs/reference/, regenerated
automatically by 'make regen' alongside the api/ codegen
- New 'make docs' target installs gomarkdoc on first run; 'make
docs-check' is a CI gate
- Fold doc-clean assertion into existing codegen-clean job (single
diff check covers spec + api + reference)
- Rewrite README header: logo via <picture>, friendlier tagline,
emoji-led 'Why you'll like it' bullets instead of Why-table
- Drop duplicate echo snippet, soften 'Codegen pipeline' section into
'Keeping up with Telegram'
- Link reference from README, Pages nav, and a new Markdown reference
card on index.html (target = GitHub source view, renders .md natively)
