Commit 7c4229c0 leads to degenerate zone geometry
# Description
Commit 7c4229c066901ffb57ab518103a7345f2ad8d217 fixed the minimum zone width not respected issue, but introduced degenerate zone geometry instead. This happens whenever 2 zones of the same net overlap. This is a regression compared to both v9 and v10 before the commit.
{width=146 height=313}{width=341 height=258}
There are also weird fingers even within a single zone:
{width=233 height=258}
# Steps to reproduce
1. Create 2 overlapping zones on the same net
2. fill zones
# KiCad Version
```
Application: KiCad PCB Editor x86_64 on x86_64
Version: 10.0.0-rc2-483-g10592c242d, release build
Libraries:
wxWidgets 3.2.8
FreeType 2.14.1
HarfBuzz 12.3.2
FontConfig 2.17.1
libcurl/8.7.1 (SecureTransport) LibreSSL/3.3.6 zlib/1.2.12 nghttp2/1.68.0
Platform: macOS Version 26.3 (Build 25D125), 64 bit, Little endian, wxMac
OpenGL: ATI Technologies Inc., AMD Radeon Pro 5300M OpenGL Engine, 2.1 ATI-7.1.6
Build Info:
Date: Mar 10 2026 01:17:18
wxWidgets: 3.2.8 (wchar_t,wx containers)
Boost: 1.90.0
OCC: 7.9.3
Curl: 8.7.1
ngspice: 45.2
Compiler: Clang 17.0.0 with C++ ABI 1002
KICAD_IPC_API=ON
KICAD_USE_PCH=OFF
```
issue