[Feature request] Upon cancelling bolus triggered by Bolus wizard, prompt to remove Carbs added by wizard for that event

As a user, I'd like to be prompted to remove the carbs added by the bolus wizard if I cancel the bolus, so that the loop doesn't then assume COB is higher than reality, given the bolus was cancelled due to no longer eating or changing the amount being eaten.

Example

1. User opens Bolus wizard and enters 70g carbs for meal.
2. Bolus of 7U started.
3. User realises carb count was too high and cancels bolus after 0.05U is administered.
4. User then opens Bolus wizard again and enters the correct amount of carbs, being 50g.
5. Bolus of 5U is administered.
6. User has eaten 50g but the logged COB is 120g (70g + 50g from two events).
7. Loop administers an additional 5U over the next two hours via SMBs to handle the additional 70g that was not consumed, resulting in hypo.

Start by tracing the Bolus wizard flow from bolus cancellation through the carb event recorded for that bolus. Check how a cancelled delivery and its associated carbs are represented, then verify that the user can remove those carbs while retaining the correctly administered event; the issue provides no file or test names.