[APIView] Epic: Approvals Version-Level Approvals

## Overview

Version-level approvals for APIView. Moves approval from per-revision to per-version, replaces opaque carry-forward with policy-driven inheritance, makes release gating and Copilot triggers version-aware, and updates the Angular SPA.

## Work Items

- [ ] #15005 — WI-14: Approval Inheritance Policy & ClassifyTransition
- [ ] #15006 — WI-15: Version-Level Approval Backend
- [ ] #15007 — WI-16: GetReviewStatus & Copilot Trigger
- [ ] #15008 — WI-17: Approval SPA Update

## Dependency Chain

```
WI-14 ──┐
├── WI-15 ←→ WI-17 (flip together)
WI-3 ───┘
WI-3 → WI-16
```

WI-14 can be developed in parallel with Foundation (WI-1). WI-16 is independently deployable.

⚠️ **Stable-state gate:** WI-15 + WI-17 must have their feature flag flipped together. The backend expects version-level approval calls and the SPA must be sending them.

Start with the linked work items WI-14 through WI-17 to understand the approval inheritance, backend, review-status, Copilot, and Angular SPA scopes. Follow the dependency chain before choosing a component. Done requires the backend and SPA changes to work together, with the WI-15 and WI-17 feature flag flipped together for a stable version-level approval flow.

Written by the indexing model from the issue text.