v2.0.0

chore: prepare repository for HACS default catalog submission

- hacs.json: add country "IT" (CAME is an Italian brand)
- README.md: update HACS badge from Custom to Default, add my.home-assistant.io
  quick-install button
- .github/workflows/validate.yml: HACS + hassfest validation on push/PR/schedule
- .github/workflows/release.yml: validate tag vs manifest version on release

https://claude.ai/code/session_01JDRaBiYN47kXt1uWhkgrv4