ios: TaskViewModel observes $allTasks and filters by residence in-memory

Replaces the dual-sink ($allTasks when residence-scoped is nil,
$tasksByResidence when set) with a single $allTasks observation
that filters in-memory when currentResidenceId is set.

Eliminates the gitea#2 race window where the per-residence cache slot
could be empty while $allTasks was populated, leaving residence
detail stuck on the empty state. After this commit, every emit of
_allTasks rerenders every observing view — kanban tab, residence
detail, dashboards — atomically.

Refs gitea#2

iosApp/iosApp/Task/TaskViewModel.swift

@@ -42,6 +42,12 @@ class TaskViewModel: ObservableObject {
     private let dataManager: DataManagerObservable
 
     // MARK: - Initialization
+    /// Single source of truth = DataManager._allTasks. When this VM is
+    /// residence-scoped (currentResidenceId set), filter in-memory by
+    /// residence id. Eliminates the gitea#2 race window where the
+    /// per-residence cache slot could be empty while _allTasks was
+    /// populated. The per-residence cache is gone (cec521b).
+    ///
     /// - Parameter dataManager: Observable cache the VM subscribes to.
     ///   Defaults to the shared singleton. Tests inject a fixture-backed
     ///   instance so populated-state snapshots render real data.
@@ -50,35 +56,26 @@ class TaskViewModel: ObservableObject {
 
         // Seed from current cache so snapshot tests/previews render
         // populated state without waiting for Combine's async dispatch.
+        // The seed path mirrors the steady-state filter below — if this
+        // VM is residence-scoped at construction time the seed has to
+        // pre-filter too, but currentResidenceId is set after init via
+        // setResidenceFilter(...), so seeding the unfiltered list is fine.
         self.tasksResponse = dataManager.allTasks
 
-        // Observe injected DataManagerObservable for all tasks data
+        // Observe injected DataManagerObservable for all tasks data.
         dataManager.$allTasks
             .receive(on: DispatchQueue.main)
             .sink { [weak self] allTasks in
-                // Skip DataManager updates during completion animation to prevent
+                guard let self else { return }
-                // the task from being moved out of its column before the animation finishes
+                guard !self.isAnimatingCompletion else { return }
-                guard self?.isAnimatingCompletion != true else { return }
-                // Only update if we're showing all tasks (no residence filter)
-                if self?.currentResidenceId == nil {
-                    self?.tasksResponse = allTasks
-                    if allTasks != nil {
-                        self?.isLoadingTasks = false
-                    }
-                }
-            }
-            .store(in: &cancellables)
 
-        // Observe tasks by residence
+                if let allTasks {
-        dataManager.$tasksByResidence
+                    if let resId = self.currentResidenceId {
-            .receive(on: DispatchQueue.main)
+                        self.tasksResponse = self.filterTasks(allTasks, residenceId: resId)
-            .sink { [weak self] tasksByResidence in
+                    } else {
-                guard self?.isAnimatingCompletion != true else { return }
+                        self.tasksResponse = allTasks
-                // Only update if we're filtering by residence
+                    }
-                if let resId = self?.currentResidenceId,
+                    self.isLoadingTasks = false
-                   let tasks = tasksByResidence[resId] {
-                    self?.tasksResponse = tasks
-                    self?.isLoadingTasks = false
                 }
             }
             .store(in: &cancellables)
@@ -392,6 +389,28 @@ class TaskViewModel: ObservableObject {
         }
     }
 
+    /// Filter the all-tasks kanban down to a single residence in-memory.
+    /// Mirrors `DataManager.getTasksForResidence` on the Kotlin side.
+    private func filterTasks(_ response: TaskColumnsResponse, residenceId: Int32) -> TaskColumnsResponse {
+        let filteredColumns = response.columns.map { column -> TaskColumn in
+            let filteredTasks = column.tasks.filter { Int32($0.residenceId) == residenceId }
+            return TaskColumn(
+                name: column.name,
+                displayName: column.displayName,
+                buttonTypes: column.buttonTypes,
+                icons: column.icons,
+                color: column.color,
+                tasks: filteredTasks,
+                count: Int32(filteredTasks.count)
+            )
+        }
+        return TaskColumnsResponse(
+            columns: filteredColumns,
+            daysThreshold: response.daysThreshold,
+            residenceId: String(residenceId)
+        )
+    }
+
     /// Updates a task in the kanban board by moving it to the correct column based on kanban_column
     func updateTaskInKanban(_ updatedTask: TaskResponse) {
         guard let currentResponse = tasksResponse else { return }