feat: add jump to now/day on mobile agenda

[NGPixel]

• Adds a "Jump to Now / specific day" menu on the agenda page, on mobile. (closes Agenda "Now" link not available on mobile platforms #6621)
• Removes the super long menu item text for the calendar ics link, which isn't always detected properly on mobile. (fixes Long titles in menus on mobile agenda #6623)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (522443a) 88.83% compared to head (951e264) 88.83%.
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6654   +/-   ##
=======================================
  Coverage   88.83%   88.83%           
=======================================
  Files         285      285           
  Lines       40222    40222           
=======================================
  Hits        35730    35730           
  Misses       4492     4492           

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