Define minimal data model for the KI register (AI register) for BOD

### Description

### Background

Policy requires that we have an overview of AI tools and use cases in use. KITT needs a minimal “KI-register” for BOD.

Norwegian justification:

> Policy krever oversikt over hvilke KI-verktøy og bruksområder som er i bruk i virksomheten.

### In scope

_No response_

### Out of scope

_No response_

### Additional Information

_No response_

### Tasks

### Tasks

- [ ] Define which fields the register must contain for each entry, e.g.:
- [ ] Use case ID / name
- [ ] Product/team
- [ ] Owner (role + person)
- [ ] Short description
- [ ] Data classes involved
- [ ] Personal data? (yes/no)
- [ ] Tool(s) used
- [ ] Risk assessment done? (yes/no/link)
- [ ] Status (idea / experiment / pilot / in production / stopped)
- [ ] Last review date
- [ ] Document the data model in `/guides/ai-register-model.md`.
- [ ] Propose 1–2 implementation options:
- [ ] Simple: table in Confluence/SharePoint or any opther tool that makes the experience better such as Backsida
- [ ] “Dev-friendly”: YAML/JSON files in this repo that can be synced/exported.

### Definition of Done

- [ ] We have a clear, agreed list of fields for the KI register.
- [ ] The model is simple enough for teams to understand in under 2 minutes.
- [ ] Future implementation work (next issue) can use this model directly.