Proof Details screen — display requested claims and consent

### Description
Implement the **Proof Details** screen (`/presentation/details`) — design screen `Desktop-13`.

### UI spec
- Header: `"Proof Details"` with a back `<` button
- Bold section heading: `" is requesting the following credentials:"`
- A list of claim name/value pairs (e.g. `Username: francis`)
- **Share** (primary, green) and **Decline** (secondary, outlined) buttons at the bottom

### Acceptance criteria
- [ ] Verifier name and requested claims are rendered from selected credential + parsed request (mocked)
- [ ] Tapping **Share** triggers a stub `presentCredential()` call and navigates to `/presentation/success`
- [ ] Tapping **Decline** navigates to `/` and clears all presentation state
- [ ] Share button shows a loading/spinner state while the stub call is in progress
- [ ] Unit tests cover both the Decline and Share paths

### Notes
Only claims requested via `dcql_query` / `presentation_definition` should be shown — display all mock claims for now, enforce filtering once the backend spec lands.
OID4VP spec ref: §6.3 (Claims Query), §15.1 (User Consent), §15.4 (Selective Disclosure).