PD Previews: Linear/Polar/Multipattern (maybe Mirror too) could highlight the first feature different

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Problem description

The new preview feature is excellent.
Currently, in PD Patterns, all occurrences are shown in the same color.
I’d like to suggest that the original/base feature be highlighted slightly differently so the user can quickly identify the originating feature.

### Full version info

```shell
OS: Ubuntu 25.04 (ubuntu:GNOME/ubuntu-xorg/xcb)
Architecture: x86_64
Version: 1.1.0dev.14555 (Git shallow)
Build date: 2025/09/12 03:41:38
Build type: Release
Branch: main
Hash: 952bff5b63a62b55a7ea1623edfb39e90dee2d4c
Python 3.11.13, Qt 6.8.3, Coin 4.0.3, Vtk 9.3.1, boost 1_86, Eigen3 3.4.0, PySide 6.8.3
shiboken 6.8.3, xerces-c 3.3.0, IfcOpenShell 0.8.2, OCC 7.8.1
Locale: English/United States (en_US)
Navigation Style/Orbit Style/Rotation Mode: Touchpad/Trackball/Drag at cursor
Stylesheet/Theme/QtStyle: OpenDark.qss/OpenDark/
Logical DPI/Physical DPI/Pixel Ratio: 96/94.0767/1
Installed mods:
* Assembly4.1 0.60.2.1
* Cables 0.2.1
* CurvesWB 0.6.64
* FreeCAD-render 2024.12.15
* sheetmetal 0.7.52
* DynamicData 2.75.0
* Curves 0.6.70
* InventorLoader 1.5.1
* diff-tools 0.1.0
* ose-piping
* OpenTheme 2025.5.20
* fasteners 0.5.41
* Silk 0.2.0
* osh-autodoc-workbench 0.2.3
* CurvedShapes 1.0.13
* freecad-povray-render
* OpticsWorkbench 1.2.2
* lattice2 1.0.0
* kicadStepUpMod 11.7.6
```

### Subproject(s) affected?

PartDesign

### Anything else?

_No response_

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Reproduce the PartDesign preview behavior described for Linear, Polar, and Multipattern, and check whether Mirror uses the same path. Trace the preview implementation from the PartDesign entry point; done means the original feature is visibly distinct from generated occurrences while the preview remains consistent across the affected patterns.

Written by the indexing model from the issue text.