FX.118 SuperCad dialogs and pages: dropdowns, text fields and notes boxes had no styling; a stray "null" showed in the Timer and the event form

Wrong: selects in the Timer, Calendar, Teams and Settings dialogs were the browser's small native control, text/date fields and notes boxes were plain white boxes (the time zone field stayed narrow), and the Timer and the calendar event form printed the word "null" where an optional field was left out (empty placeholders were passed straight to replaceChildren). Changed: one rule gives selects, text/date/number fields and textareas the same border, height, colours and focus outline; the empty placeholders are dropped before drawing; the event form's ten reminder ticks lay out in columns. Tests: home-calendar checks no stray null/undefined text in the form. Untested: browsers other than headless Chromium.