[Feature Request] Add view tracking and visibility for shared artifacts

**Bug Description**
artifacts that are selectively shared should provide some visibility into whether or not the person you shared it to has viewed it. artifacts shared to an org should allow the owner to see who from the org has viewed it (or at least enable this as a selectable capability)

**Environment Info**
- Platform: darwin
- Terminal: iTerm.app
- Version: 2.1.246
- Feedback ID: 52ed9026-f2b6-42dd-8948-aac916415445

**Errors**
```json
[]
```

No files, tests, or entry points are named. Start by locating how shared artifacts, selective recipients, and organization access are represented, then define the view-tracking capability and its privacy or opt-in boundaries; done means owners can determine who viewed a shared artifact where the requested capability is enabled.

索引モデルが issue の本文から書いたものです。