BusFault Cleanup

[lukelowry]

Description

Follow-up to #607. Removes BusFault and uses Bus::setFault throughout. Solver fault events now name the bus directly.

Proposed changes

• Remove BusFault, getBusFault, and case-file fault definitions.
• Solver events use bus, with R and X specified for fault_on.
• ContingencyAnalysis faults each bus in turn.
• Update examples, tests, plotting, and documentation.

Checklist

• All tests pass.
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• The new code follows GridKit™ style guidelines.
• There are unit tests for the new code.
• The new code is documented.
• The feature branch is rebased with respect to the target branch.
• The CHANGELOG.md has been updated to reflect the changes.

Further comments

None.

[nkoukpaizan]

Thanks for the well-scoped PR. I have a few comments, but otherwise looks good.

[lukelowry]

@pelesh @isatkaus Pending your review!

[pelesh]

Well scoped and nicely executed PR.

The tolerance change in TenGen example is concerning; we need to investigate this further.

Given that key validation tests pass, I suggest we merge this.