fix(i18n): unify the calendar titles on one locale-aware formatter (#60)

Month, Week and Day each hand-rolled their title from a German-style template —
"$weekday, ${date.day}. $monthName ${date.year}" — so every language got a
trailing ordinal dot and day-before-month order, including ones that write the
month first. English read "Fri, 17. Jul 2026" where it should read
"Fri, Jul 17, 2026".

396a561 already fixed exactly this, but only for Agenda: it added
localizedDateFormatter and migrated the four agenda files, leaving Month, Week,
Day and MonthWidget on their originals. Day and Agenda therefore disagreed about
the same date. All four now route through formatCalendarTitle, so there is one
place left that decides how a title reads.

Two behaviour changes fall out of the reporter's point that the bar wastes space:

The year is dropped while you are in the current year. The title sits above a
grid that already says which year it is; the year's absence is itself the signal
that you are in the current one, and it reappears when you page out — the moment
it starts carrying information. Since a skeleton is a field list, this is just
appending "y", and the locale still places it.

The Week title names a month instead of a day range. "24. Jun – 31. Jun" restated
the day numbers printed in the column headers directly below, in the widest
string in the bar. Naming weekStart's month keeps a straddling week on the
outgoing month until it is fully gone — a week is seven contiguous days, so the
earlier month has a day in it exactly while weekStart is inside it. No straddle
conditional, and the title depends on nothing but weekStart, so it cannot drift
with the direction you paged in from.

currentLocale/localizedDateFormatter move to floret-kit's core-locale (neither is
calendar-specific); LocaleSupport.kt goes away and its 11 callers repoint.
MonthWidget keeps Locale.getDefault() — Glance has no LocalConfiguration and the
widget re-renders on a configuration change, matching AgendaWidget.

Does not touch the FAB stack the issue opens with: the buttons overlaying content
is intentional and matches Google Calendar.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,24 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Changed
+- Dates in the Month, Week and Day title bars now follow your language's own
+  conventions. They were laid out in a fixed German-style order with a trailing
+  dot on the day number — "Fri, 17. Jul 2026" — in every language, including
+  ones that write the month first; the Agenda view already read correctly, so the
+  two disagreed about the same date. All four views now share one formatter and
+  render "Fri, Jul 17, 2026" in English, "17. Juli 2026" in German, and so on
+  ([#60]).
+- The title bar drops the year while you're in the current one — "July" rather
+  than "July 2026". The year reappears the moment you page out of the current
+  year, which is when it tells you something you didn't already know.
+- The Week view's title now names the month instead of spelling out the day range.
+  "24. Jun – 31. Jun" restated the day numbers already printed in the column
+  headers right below it, in the widest string in the bar. A week that straddles
+  two months keeps the outgoing month until it is fully gone ([#60]).
+
 ## [2.15.0] — 2026-07-15
 
 ### Added
@@ -997,3 +1015,4 @@ automatically, with zero telemetry and no internet permission.
 [#48]: https://codeberg.org/jlmakiola/calendula/issues/48
 [#49]: https://codeberg.org/jlmakiola/calendula/issues/49
 [#52]: https://codeberg.org/jlmakiola/calendula/issues/52
+[#60]: https://codeberg.org/jlmakiola/calendula/issues/60