feat(edit): form redesign, optional fields, OptionCard dialogs, expressive motion

Post-v1.2.0 design iteration on the event form, reviewed slice by slice
on-device:

- Form rebuilt on the detail screen's card system: tonal EditCards with
  gutter icons (centred on the first row, top-aligned for multiline),
  borderless inline fields (placeholders at half opacity), calendar-coloured
  title accent, no dividers, bare top bar
- Optional sections (location, description, reminders, availability,
  visibility) with per-user defaults in Settings ("New event form" toggles);
  hidden ones unfold via a "More fields" picker dialog
- Reminders: stacked rows + full-width borderless add; two-step picker
  (one-tap presets, then custom amount + minutes/hours/days/weeks dropdown);
  written as METHOD_ALERT Reminders rows. Availability busy/free segmented
  toggle; visibility selector with per-level icons
- OptionCard (ui/common) is now the app-wide selection-dialog standard;
  calendar picker, visibility, more-fields, reminder presets and the
  recurring-delete chooser all use it — radio-row dialogs removed
- MaterialExpressiveTheme with MotionScheme.standard() (expressive bounce
  felt overdone); FAB stack + field reveals animate on theme springs;
  jump-to-today slides toward today's actual direction
- IME: adjustResize + imePadding so the keyboard never pans the form
- Tests: form-field prefs round-trips, availability/access provider
  mappings; DE+EN strings throughout

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,37 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- Optional event-form fields with user-controlled defaults: reminders,
+  availability (busy/free), and visibility (default/public/private/
+  confidential) joined location and description as form sections. Settings
+  gained a "New event form" section choosing which show by default; the rest
+  unfold via a "More fields" picker
+- Reminders editor: stacked rows with right-bound remove, full-width add
+  action; the picker offers one-tap presets and a custom amount + unit
+  (minutes/hours/days/weeks) step
+- `OptionCard` — the app's standard selection-dialog row (full-width tonal
+  card, optional icon + supporting line, highlighted selection). All dialogs
+  (calendar, visibility, more-fields, reminder presets, recurring-delete)
+  now use it; radio-row dialogs are retired
+
+### Changed
+- Event form redesigned onto the detail screen's design system: tonal cards
+  with gutter icons (top-aligned on tall cards), borderless inline text
+  fields, calendar-coloured accent bar under the title, no dividers, no
+  top-bar title; placeholders render clearly fainter than input
+- M3 Expressive motion: the theme now provides a MotionScheme
+  (`MaterialExpressiveTheme`, standard springs — expressive bounce reviewed
+  as overdone), the FAB stack and "more fields" reveals animate on theme
+  springs
+- The jump-to-today slide is direction-aware (future → today slides in from
+  the left, past → from the right)
+
+### Fixed
+- The keyboard no longer pans the whole event form; the screen stays
+  anchored and the focused field scrolls into view (`adjustResize` +
+  `imePadding`)
+
 ## [1.2.0] — 2026-06-11
 
 ### Added