Add shared utilities and refactor iOS codebase for DRY compliance

Create centralized shared utilities in iosApp/Shared/:
- Extensions: ViewExtensions, DateExtensions, StringExtensions, DoubleExtensions
- Components: FormComponents, SharedEmptyStateView, ButtonStyles
- Modifiers: CardModifiers
- Utilities: ValidationHelpers, ErrorMessages

Migrate existing views to use shared utilities:
- LoginView: Use IconTextField, FieldLabel, FieldError, OrganicPrimaryButton
- TaskFormView: Use .loadingOverlay() modifier
- TaskCard/DynamicTaskCard: Use .toFormattedDate() extension
- CompletionCardView: Use .toCurrency() (with KotlinDouble support)
- ResidenceDetailView: Use OrganicEmptyState, StandardLoadingView
- Profile views: Use .standardFormStyle(), .sectionBackground()
- Form views: Use consistent form styling modifiers

Benefits:
- Eliminates ~180 lines of duplicate code
- Consistent styling across all forms and components
- KotlinDouble extensions for seamless KMM interop
- Single source of truth for UI patterns

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

iosApp/iosApp.xcodeproj/project.pbxproj

@@ -135,6 +135,7 @@
 			isa = PBXFileSystemSynchronizedBuildFileExceptionSet;
 			membershipExceptions = (
 				Assets.xcassets,
+				Shared/TaskStatsCalculator.swift,
 			);
 			target = 1C07893C2EBC218B00392B46 /* CaseraExtension */;
 		};