[codebymini]

Summary

Time in range cut-offs are now defined in one place, the range mode is picked from a clearer full-width list, and a new mode is added: Extended Tight Range (TING, 63–140 mg/dL).

Why

• The cut-offs were repeated. 54, 70, 140, 180 and 250 mg/dL were written out separately in the stats, GRI, the settings footer and the Live Activity, so a change in one place could miss the others.
• Adding a mode meant touching many files. Each one needed edits to several switch statements, the segmented picker, the settings footer and the stats card toggle.
• The segmented picker didn't scale. A fourth option made each segment cramped, and the full names and ranges had to go in a separate footer.

What changed

Cut-offs in one place

• New GlucoseThresholds in Shared/, so the app, Live Activity and watch targets all use the same values. It holds the very low/very high cut-offs and each mode's low/high.
• TIRCalculator, TIRView, GRICalculator and the Live Activity background tint now read from it. GRI keeps the standard 70–180 range whichever mode is selected, as its definition requires.

Range modes describe themselves

• Each TimeInRangeDisplayMode now has a title, fixedThresholds and next.
• effectiveThresholds(), the stats title and the stats card toggle use these instead of their own switch statements.
• Adding a mode is now: its cut-offs in GlucoseThresholds, plus one case with a title and thresholds. The settings, stats, chart lines, header, watch and Live Activity pick it up from there.

Range settings

• The segmented TIR/TITR/Custom picker and its footer are replaced by a single row. It shows the selected mode's full name with its cut-offs, e.g. Time in Tight Range 3,9–7,8.

• Tapping the row opens a Range list with one line per mode (name, cut-offs, checkmark). Picking a fixed mode goes back.
• Picking Custom Range stays on the list and shows the Low and High pickers there, so the settings page no longer changes height when you switch modes.
• The onboarding Statistics page now has a navigation stack, with its bar hidden, so the list can open from there too.

Extended Tight Range (TING)

• A new mode for 63–140 mg/dL (3,5–7,8 mmol/L): the tight range with its lower cut-off moved down from 70, also known as Time in Normoglycemia.
• It's shown as Extended Tight Range and sits between Time in Tight Range and Custom Range.
• Settings search finds Range Mode for "ting" and "extended".

[marionbarker]

Approved by test.