* Add instructions to create commerce b2b store from vibes
* update rule and sf commands
* Refactor Commerce B2B skill: rename and flatten directory structure
- Rename skill from create-b2b-commerce-storefront to creating-b2b-commerce-store to better reflect what users actually create (the Store, not the Storefront)
- Flatten directory from skills/commerce/create-b2b-commerce-storefront/ to skills/creating-b2b-commerce-store/ to match repository pattern
- Remove old prompts and rules consolidated into skill
- Remove Commerce prompt and rule entries from manifest.json (consolidated into skill)
