feat(nav): jump-to-date action in the navigation drawer

Add a "Jump to date" row to the drawer (under the View switcher) that
opens an M3 date picker and navigates the active view to the chosen day,
sliding in from the correct side. Wired across Month/Week/Day, each
seeding the picker with its visible anchor (day / week-start / 1st-of-month).

Extract the form's private date-picker into a shared
ui/common/CalendarDatePickerDialog so the event form and the drawer share
one picker; add goToDate() to the Month and Week view models.

Reprioritises the roadmap: jump-to-date is now next; duplicate-event drops
to the bottom as low-importance.

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

app/src/main/res/values/strings.xml

@@ -199,6 +199,9 @@
     <string name="view_day">Day</string>
     <string name="view_section">View</string>
 
+    <!-- Jump to date (drawer) -->
+    <string name="drawer_jump_to_date">Jump to date</string>
+
     <!-- Calendar filter (M3) -->
     <string name="filter_title">Calendars</string>