refactor: getTasksByResidence is now a thin filter over _allTasks

Was 3 fallback paths (per-residence cache → filter from allTasks →
network). Now: ensure _allTasks fresh, return filter. The per-residence
cache becomes write-only by this path, scheduled for deletion in the
next commit.

Eliminates a class of bugs where the per-residence cache slot could
be missing while _allTasks was stale — the old Path 1+2 would either
return stale data or skip and hit the API redundantly.

composeApp/src/commonMain/kotlin/com/tt/honeyDue/network/APILayer.kt

@@ -615,37 +615,23 @@ object APILayer {
         return result
     }
 
+    /**
+     * Returns kanban data for a single residence. Single source of truth
+     * is `_allTasks`; this function ensures it's fresh, then filters.
+     *
+     * Replaces the previous 3-path implementation (per-residence cache →
+     * filter from allTasks → API) that produced inconsistent results
+     * when the per-residence cache slot was empty but `_allTasks` was
+     * stale. Phase 3 deletes the per-residence cache entirely.
+     */
     suspend fun getTasksByResidence(residenceId: Int, forceRefresh: Boolean = false): ApiResult<TaskColumnsResponse> {
-        // 1. Check residence-specific cache first
+        val allTasksResult = getTasks(forceRefresh = forceRefresh)
-        if (!forceRefresh && DataManager.isCacheValid(DataManager.tasksByResidenceCacheTime[residenceId] ?: 0L)) {
+        if (allTasksResult is ApiResult.Error) return allTasksResult
-            val cached = DataManager.tasksByResidence.value[residenceId]
-            if (cached != null) {
-                return ApiResult.Success(cached)
-            }
-        }
 
-        // 2. Try filtering from allTasks cache before hitting API (optimization)
-        // This avoids a redundant API call when we already have all tasks loaded
-        if (!forceRefresh && DataManager.isCacheValid(DataManager.tasksCacheTime)) {
         val filtered = DataManager.getTasksForResidence(residenceId)
-            if (filtered != null) {
+            ?: return ApiResult.Error("Tasks unavailable", 0)
-                // Cache the filtered result for future use
-                DataManager.setTasksForResidence(residenceId, filtered)
         return ApiResult.Success(filtered)
     }
-        }
-
-        // 3. Fallback: Fetch from API
-        val token = getToken() ?: return ApiResult.Error("Not authenticated", 401)
-        val result = taskApi.getTasksByResidence(token, residenceId)
-
-        // Update DataManager on success
-        if (result is ApiResult.Success) {
-            DataManager.setTasksForResidence(residenceId, result.data)
-        }
-
-        return result
-    }
 
     suspend fun createTask(request: TaskCreateRequest): ApiResult<TaskResponse> {
         val token = getToken() ?: return ApiResult.Error("Not authenticated", 401)