[MtlPhil]

A Live Activity only redraws when an update reaches it, so with no network or a stopped app it can't show that its data is old. On CarPlay that means a reading can sit there looking current long after it has stopped updating.

Staleness

• staleDate is now 12 minutes after the reading and is sent in update pushes, so iOS can flag the activity without the app.
• Renewal relies only on laRenewBy and laRenewalFailed, so stale data no longer replaces the activity when the app opens. An activity with no stored deadline is still replaced, since it could never renew.

Small family (CarPlay and the Watch Smart Stack)

• A stale reading is struck out in red, with the BG and arrow grey.
• A status line, on by default, shows the update time, IOB and COB (or Not Looping in their place) and any active override with its insulin needs, range and time left.
• While the status line is on, IOB, COB and Override aren't offered for the right slot. A stored choice of one of them comes back when the line is turned off, and turning it off also restores the original font sizes.
• A Tight CarPlay Layout switch, off by default, replaces the right slot with projected BG, IOB, COB and basal, and centres the bottom row. No API tells CarPlay from the Watch, so it also needs a width of at least 205 points: the 240-wide CarPlay layouts, not the 170-wide one.
• Both switches explain themselves in an info button.

Tests cover the stale date, renewal, override details and the small-widget layout.

A follow-up PR adds a CarPlay widget on top of this one.