refactor: Move jetstream to internal/atproto/jetstream
Groups all atProto-related code under internal/atproto/ for better
code organization:
internal/
├── atproto/
│ ├── lexicon/ # Protocol definitions
│ └── jetstream/ # Firehose consumer
├── core/ # Business logic
└── db/ # Persistence
Changes:
- Moved internal/jetstream/ → internal/atproto/jetstream/
- Updated import paths in cmd/server/main.go
- Updated import paths in all test files
All tests passing:
✅ Unit tests
✅ Integration tests
✅ E2E tests
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>