Class GoToExtremaService

Leaves the GO_TO_EXTREMA scope, returning to whichever scope opened the dialog. toggleFocus pops GO_TO_EXTREMA off the focus stack, so the restored scope is BRAILLE when the dialog was opened from braille mode and TRACE when it was opened from the chart.

The guard tests for GO_TO_EXTREMA rather than "not TRACE": the dismissal paths call this both directly and after hide() has already restored the scope, and a "not TRACE" guard would read the restored BRAILLE scope as still-open and push GO_TO_EXTREMA back onto the stack.

Jumps to a min or max point of the active trace, skipping the extrema dialog. The dialog lists every extremum the trace offers, which is what g is for; the bracket keys are the one-press shortcut to the lowest or highest value among them.

A value can be tied across several points. Rather than always landing on the first, each press steps to the next tied point and wraps at the end, so a repeated press walks them. Which one the cursor currently sits on is read back from the trace instead of being remembered here: stored state would go stale the moment the reader moved by any other means, or the data changed under a live chart.

Navigation itself goes through the same navigateToExtrema the dialog uses, so the move is announced, brailled and highlighted by the usual observer chain.