CAM: Reduce zero-cut moves in 3D Surface Rotary multi-pass - Feature Request

### Problem description

3D Surface Rotary multi-pass makes no reduction or removal of gcode that passes over the same surface repeatedly that doesn't need cutting. Would be a huge cut-time improvement if it could.
Current function appears to be to scan model depth vs stock, at each point on a single rotation, and for each linear step along the longitudinal axis. If previous passes had already reached model depth, the outcome from the depth scan is a repeated cut at model depth. Simple, but at the expense of time efficiency.

### Workbench affected?

CAM

### Steps to reproduce

Native behaviour of CAM 3D Surface Rotary multi-pass

### Expected behavior

Unnecessary cut removal/reduction to save processing time, and to reduce risk of tool 'rubbing'

### Actual behavior

No attempt appears to be made to reduce unnecessary cuts

### Development version About Info (in Safe Mode)

```shell
Confirmed as behaviour in this week's DEV build (13-May-2026)
```

### Last known good version (optional)

```shell
Confirmed as behaviour in Live 1.1.1
```