Fix for singular matrix warning

[bjorkert]

This change prevents repeated console warnings:

CGAffineTransformInvert: singular matrix

These warnings occur when the Charts library attempts to invert a transform matrix while the chart view temporarily has zero dimensions (for example before layout is complete). In this situation the matrix is singular (determinant = 0), and calling .inverted() triggers the warning.

The fix adds a simple guard before performing the inversion. If the matrix determinant is zero, .identity is returned instead of attempting the inversion.

This is safe because a singular matrix means the chart has no meaningful size yet, so there is nothing useful to transform.

Since the code lives inside a CocoaPods dependency (Charts), the fix is applied in two ways:

• A direct patch in Pods/Charts/Source/Charts/Utils/Transformer.swift
• A post_install hook in the Podfile that re-applies the patch automatically when pod install runs

This removes the warnings without affecting chart rendering or behavior.

[bjorkert]

Solves: #168

[marionbarker]

Test

This works nicely. The singular matrix indication in debug log is gone. The Nightscout plot populates much faster.
I am no longer seeing a delay before the Loop Predication is plotted on the Home screen.

[marionbarker]

Approved by code review and test.