refactor: update handle generation to use .community. format
Update PDS provisioning and Jetstream consumer to generate handles
using singular .community. instead of .communities.
Changes:
- PDSAccountProvisioner: Generate {name}.community.{domain} handles
- JetstreamConsumer: Parse and validate new handle format
- Update handle extraction logic for consistency
Example handle formats:
- gardening.community.coves.social
- gaming.community.coves.social
This maintains consistency with the lexicon schema update and aligns
with AT Protocol naming conventions.
๐ค Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>