Wire onboarding task suggestions to backend, delete hardcoded catalog

Both "For You" and "Browse All" tabs are now fully server-driven on
iOS and Android. No on-device task list, no client-side scoring rules.
When the API fails the screen shows error + Retry + Skip so onboarding
can still complete on a flaky network.

Shared (KMM)
- TaskCreateRequest + TaskResponse carry templateId
- New BulkCreateTasksRequest/Response, TaskApi.bulkCreateTasks,
  APILayer.bulkCreateTasks (updates DataManager + TotalSummary)
- OnboardingViewModel: templatesGroupedState + loadTemplatesGrouped;
  createTasks(residenceId, requests) posts once via the bulk path
- Deleted regional-template plumbing: APILayer.getRegionalTemplates,
  OnboardingViewModel.loadRegionalTemplates, TaskTemplateApi.
  getTemplatesByRegion, TaskTemplate.regionId/regionName
- 5 new AnalyticsEvents constants for the onboarding funnel

Android (Compose)
- OnboardingFirstTaskContent rewritten against the server catalog;
  ~70 lines of hardcoded taskCategories gone. Loading / Error / Empty
  panes with Retry + Skip buttons. Category icons derived from name
  keywords, colours from a 5-value palette keyed by category id
- Browse selection carries template.id into the bulk request so
  task_template_id is populated server-side

iOS (SwiftUI)
- New OnboardingTasksViewModel (@MainActor ObservableObject) wrapping
  APILayer.shared for suggestions / grouped / bulk-submit with
  loading + error state (mirrors the TaskViewModel.swift pattern)
- OnboardingFirstTaskView rewritten: buildForYouSuggestions (130 lines)
  and fallbackCategories (68 lines) deleted; both tabs show the same
  error+skip UX as Android; ForYouSuggestion/SuggestionRelevance gone
- 5 new AnalyticsEvent cases with identical PostHog event names to
  the Kotlin constants so cross-platform funnels join cleanly
- Existing TaskCreateRequest / TaskResponse call sites in TaskCard,
  TasksSection, TaskFormView updated for the new templateId parameter

Docs
- CLAUDE.md gains an "Onboarding task suggestions (server-driven)"
  subsection covering the data flow, key files on both platforms,
  and the KotlinInt(int: template.id) wrapping requirement

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -1219,6 +1219,48 @@ val CURRENT_ENV = Environment.DEV  // or Environment.LOCAL
 3. Add method to relevant ViewModel that calls APILayer
 4. Update UI to observe the new StateFlow
 
+### Onboarding task suggestions (server-driven)
+
+The First-Task onboarding screen is **fully server-driven** on both
+platforms. There is no hardcoded catalog or client-side suggestion rules;
+when the API fails the screen shows error + Retry + Skip.
+
+**Data flow:**
+
+```
+"For You" tab  → APILayer.getTaskSuggestions(residenceId)
+                 → GET /api/tasks/suggestions/?residence_id=X
+                 → scored against 15 home-profile fields (incl. climate zone)
+
+"Browse All" tab → APILayer.getTaskTemplatesGrouped()
+                 → GET /api/tasks/templates/grouped/
+                 → cached on DataManager.taskTemplatesGrouped (24h TTL)
+
+Submit          → APILayer.bulkCreateTasks(BulkCreateTasksRequest)
+                 → POST /api/tasks/bulk/
+                 → single DB transaction, all-or-nothing
+```
+
+**Key files:**
+
+- Shared ViewModel: `composeApp/.../viewmodel/OnboardingViewModel.kt`
+  (`suggestionsState`, `templatesGroupedState`, `createTasks`)
+- Android screen: `composeApp/.../ui/screens/onboarding/OnboardingFirstTaskContent.kt`
+- iOS Swift wrapper: `iosApp/iosApp/Onboarding/OnboardingTasksViewModel.swift`
+  (mirrors the Kotlin ViewModel but calls `APILayer.shared` directly in
+  Swift rather than observing Kotlin StateFlows — matches the convention in
+  `iosApp/iosApp/Task/TaskViewModel.swift`)
+- iOS view: `iosApp/iosApp/Onboarding/OnboardingFirstTaskView.swift`
+- Analytics: 5 shared event names in `AnalyticsEvents` (Kotlin) +
+  `AnalyticsEvent` (Swift) — `onboarding_suggestions_loaded`,
+  `onboarding_suggestion_accepted`, `onboarding_browse_template_accepted`,
+  `onboarding_tasks_created`, `onboarding_task_step_skipped`.
+
+**When selecting a template from either tab**, always populate
+`TaskCreateRequest.templateId` with the backend `TaskTemplate.id` so the
+created task carries the template backlink for reporting. Swift wraps the
+id as `KotlinInt(int: template.id)`.
+
 ### Handling Platform-Specific Code
 
 Use `expect/actual` pattern: