Define ChapterMembershipCubit state classes
epic-multi-chapter-membership-handling-ui-task-001 — Define all typed Cubit state classes for the chapter membership lifecycle: ChapterMembershipInitial, ChapterMembershipLoading, ChapterMembershipLoaded (with current affiliations and pending changes lists), ChapterMembershipSaving, ChapterMembershipSuccess, and ChapterMembershipError. Use freezed or manual sealed classes following the project Bloc/Cubit convention.
Acceptance Criteria
Technical Requirements
Implementation Notes
If the project uses freezed, generate the state union with `@freezed` and run `dart run build_runner build`. If not using freezed, implement a manual sealed class hierarchy using Dart 3 `sealed class` keyword — all subclasses in the same file. Prefer Dart 3 sealed classes over abstract + subclass pattern for compile-time exhaustiveness in switch. ChapterMembershipLoaded.pendingAddChapterIds and pendingRemoveAffiliationIds should be `List
ChapterMembershipFailure should be a separate sealed class (not mixed into ChapterMembershipError) so it can be reused in future service-layer error handling. Keep the state file focused: no business logic, no service imports — pure data containers only.
Testing Requirements
Unit tests (flutter_test): verify equality — two ChapterMembershipLoaded instances with identical data are equal; two with different pendingAddChapterIds are not equal. Verify ChapterMembershipFailure discriminates all error types correctly. Verify copyWith on ChapterMembershipLoaded updates only the specified field. These are pure Dart tests with zero dependencies — fast and deterministic.
Aim for 100% coverage of state class constructors and equality logic.
The Duplicate Activity Warning Dialog must announce itself to VoiceOver and TalkBack immediately on appearance. Flutter's default modal semantics do not guarantee focus shift to the dialog on all platform versions, risking silent appearance for screen reader users — a WCAG 2.2 failure.
Mitigation & Contingency
Mitigation: Wrap the dialog content in a Semantics node with liveRegion: true and explicitly request focus via FocusScope.of(context).requestFocus() on the dialog's primary action button in the post-frame callback. Test on physical iOS (VoiceOver) and Android (TalkBack) devices, not only simulators.
Contingency: If automatic focus fails on a specific platform version, add a platform-specific fallback using SemanticsService.announce() to force a live region announcement of the dialog's headline text.
The Chapter Membership Cubit tracks pending changes before commit to support the two-step add/confirm flow. If the user navigates away mid-edit or the app is backgrounded, uncommitted pending state could be replayed incorrectly on return, causing phantom affiliation additions or removals.
Mitigation & Contingency
Mitigation: Design the Cubit to hold pending changes only in transient in-memory state with no persistence. On any navigation-away event, emit a reset state that discards pending changes. Prevent accidental navigation during an active edit by showing a discard-changes confirmation dialog.
Contingency: If state desync is reported in production, add an explicit state reconciliation step in the Cubit's onResume handler that re-fetches the authoritative affiliation list from the repository and resets all pending state before re-rendering.
The Chapter Assignment Editor's searchable chapter list must load quickly. If the organisation has hundreds of chapters (NHF has 1,400 local chapters) and the full list is fetched on dialog open, the editor will be slow to display and the search will be sluggish.
Mitigation & Contingency
Mitigation: Scope the chapter list to only chapters within the coordinator's administrative scope (not all 1,400), leveraging the existing hierarchy access scope service. Implement server-side search with a minimum 2-character threshold and debounce to avoid excessive Supabase queries.
Contingency: If the scoped list is still too large, add local caching of the chapter list with a 15-minute TTL and an explicit refresh button, ensuring the editor is always responsive even on poor network conditions.