Make Month-Day dynamic translations strings

Make Translation strings for dates that have both Month and Day have the day be an enriched value.

E.g. replace t("September1") with something more like t.rich("DayOfSeptember", {day: 1}).

We'd need to go through all of the translations manually because of the following type of issue:
If you want to translate "September 1" into Spanish, you typically get "1 de Setembro", so trying to translate "September {day}" would map to "Setembro {day}" which isn't correct.

At the end of the day, let's get 12 new translation strings: "DayOfSteptember" and so forth which map to the intelligent equivalent such as "{day} de Septembro".

When there is an instance of a specific date (like "FABStartDateSep1"), replace it with the enriched version so we don't have to add more translation strings if the start date changes to September 2.

@claude give this one a go. Please make sure that all of the translation jsons are updated appropriately.

Search the translation JSONs and the codebase for date strings such as "September1" and "FABStartDateSep1"; first inventory every Month-Day translation and its current usage. Update all 12 month-day translations and date-specific usages so the day is an enriched value, then verify that every translation JSON is consistent and the changed dates render correctly.