fix(backlog): honor configured completed statuses

frontend/src/lib/features/collections/CollectionBacklog.svelte

@@ -279,12 +279,12 @@
       const membership = await resolveCreatedItemMembership(newItem, {
         workspaceId,
         collectionId,
-        subFilterQL: collectionStore.subFilterQL ? collectionStore.effectiveSubFilterQL : '',
+        subFilterQL: collectionStore.effectiveBacklogSubFilterQL,
       });
       if (membership === 'member') {
-        // insertCreatedItem deduplicates by id so a repeated create event cannot
-        // append the same backlog row twice.
-        collectionStore.insertCreatedItem(newItem, { backlog: true });
+        // Backlog membership also depends on configured statuses, so let the
+        // authoritative backlog request decide whether the new item belongs.
+        scheduleCollectionReconciliation();
       } else if (membership === 'unknown') {
         scheduleCollectionReconciliation();
       }
@@ -439,7 +439,7 @@
       const boundaryItem = await items.getBacklogBoundary(
         workspaceId,
         collectionId,
-        collectionStore.effectiveSubFilterQL,
+        collectionStore.effectiveBacklogSubFilterQL,
         boundary,
       );
       if (!boundaryItem || boundaryItem.id === item.id) return;

frontend/src/lib/features/collections/collectionFilters.js

@@ -0,0 +1,9 @@
+/**
+ * Applies the optional completed-item visibility filter used by collection
+ * views. Backlogs pass hideCompleted=false because their configured status IDs
+ * are already the authoritative visibility rule.
+ */
+export function collectionSubFilterQL(subFilterQL = '', { hideCompleted = true } = {}) {
+  if (!hideCompleted) return subFilterQL;
+  return subFilterQL ? `(${subFilterQL}) AND status_completed = false` : 'status_completed = false';
+}

frontend/src/lib/stores/collectionContext.svelte.js

@@ -2,6 +2,7 @@ import { collections } from '../api/collections.js';
 import { items as itemsApi } from '../api/items.js';
 import { BACKGROUND_READ, FOREGROUND_READ } from '../api/readScheduler.js';
 import { normalizeCompletedLimit } from '../features/collections/boardConfigPayload.js';
+import { collectionSubFilterQL } from '../features/collections/collectionFilters.js';
 import {
   fetchCollectionBacklog,
   fetchCollectionItemChanges,
@@ -159,10 +160,11 @@ class CollectionStore {
   showCompleted = $state(false);
 
   get effectiveSubFilterQL() {
-    if (this.showCompleted) return this.subFilterQL;
-    return this.subFilterQL
-      ? `(${this.subFilterQL}) AND status_completed = false`
-      : 'status_completed = false';
+    return collectionSubFilterQL(this.subFilterQL, { hideCompleted: !this.showCompleted });
+  }
+
+  get effectiveBacklogSubFilterQL() {
+    return collectionSubFilterQL(this.subFilterQL, { hideCompleted: false });
   }
 
   #completionPreferenceKey(wsId, colId, view) {
@@ -506,7 +508,7 @@ class CollectionStore {
           ? fetchCollectionBacklog(wsId, colId, {
               page: 1,
               limit: DEFAULT_PAGE_SIZE,
-              sub_ql: this.effectiveSubFilterQL || undefined,
+              sub_ql: this.effectiveBacklogSubFilterQL || undefined,
               collection,
               requestOptions: FOREGROUND_READ,
             })
@@ -1173,7 +1175,7 @@ class CollectionStore {
       const result = await fetchCollectionBacklog(this.#wsId, this.#colId, {
         page: nextPage,
         limit: this.backlogPagination?.limit ?? DEFAULT_PAGE_SIZE,
-        sub_ql: this.effectiveSubFilterQL || undefined,
+        sub_ql: this.effectiveBacklogSubFilterQL || undefined,
         requestOptions: BACKGROUND_READ,
       });
 
@@ -1288,7 +1290,7 @@ class CollectionStore {
               this.#wsId,
               this.#colId,
               backlogLimit,
-              this.effectiveSubFilterQL || undefined,
+              this.effectiveBacklogSubFilterQL || undefined,
               collection,
               loadId
             )
@@ -1514,7 +1516,10 @@ class CollectionStore {
 
       const changes = await fetchCollectionItemChanges(this.#wsId, this.#colId, {
         since: this.#changesWatermark,
-        sub_ql: this.effectiveSubFilterQL || undefined,
+        sub_ql:
+          (BACKLOG_VIEWS.has(this.#currentView)
+            ? this.effectiveBacklogSubFilterQL
+            : this.effectiveSubFilterQL) || undefined,
       });
       if (loadId !== this.#loadId) return false;
       const nextWatermark = changes?.watermark ?? this.#changesWatermark;
@@ -1593,7 +1598,10 @@ class CollectionStore {
     const wsId = this.#wsId;
     const colId = this.#colId;
     const changes = await fetchCollectionItemChanges(wsId, colId, {
-      sub_ql: this.effectiveSubFilterQL || undefined,
+      sub_ql:
+        (BACKLOG_VIEWS.has(this.#currentView)
+          ? this.effectiveBacklogSubFilterQL
+          : this.effectiveSubFilterQL) || undefined,
     });
     if (loadId !== this.#loadId || wsId !== this.#wsId || colId !== this.#colId) return;
     this.#changesWatermark = changes?.watermark ?? 0;
@@ -1610,6 +1618,9 @@ class CollectionStore {
   }
 
   #hideCompletedItem(item) {
+    // Backlog membership is defined by the configured status IDs, which may
+    // intentionally include completed statuses.
+    if (BACKLOG_VIEWS.has(this.#currentView)) return false;
     if (this.showCompleted) return false;
     const status =
       workspaceDataStore.statuses.find((candidate) => candidate.id === item.status_id) ??

internal/repository/item_list.go

@@ -1159,21 +1159,34 @@ func (r *ItemRepository) scanItemList(rows *sql.Rows) ([]models.Item, error) {
 }
 
 // GetBacklogStatusIDs returns status IDs for backlog items.
-// It first checks board_configurations for the workspace, then falls back to non-completed statuses.
-func (r *ItemRepository) GetBacklogStatusIDs(workspaceID int) ([]int, error) {
-	return r.GetBacklogStatusIDsContext(context.Background(), workspaceID)
+// It first checks board_configurations for the collection or workspace, then
+// falls back to the global non-completed statuses.
+func (r *ItemRepository) GetBacklogStatusIDs(workspaceID, collectionID int) ([]int, error) {
+	return r.GetBacklogStatusIDsContext(context.Background(), workspaceID, collectionID)
 }
 
 // GetBacklogStatusIDsContext is the request-aware form of GetBacklogStatusIDs.
-func (r *ItemRepository) GetBacklogStatusIDsContext(ctx context.Context, workspaceID int) ([]int, error) {
-	// First, check if there's a board configuration with backlog_status_ids
-	if workspaceID > 0 {
+// A collection-scoped board configuration owns that collection's backlog
+// statuses; a request without a collection uses the workspace default. When
+// neither is configured, the global non-completed, non-default statuses apply.
+func (r *ItemRepository) GetBacklogStatusIDsContext(ctx context.Context, workspaceID, collectionID int) ([]int, error) {
+	scopeColumn, scopeID := "", 0
+	if collectionID > 0 {
+		scopeColumn, scopeID = "collection_id", collectionID
+	} else if workspaceID > 0 {
+		scopeColumn, scopeID = "workspace_id", workspaceID
+	}
+	if scopeID > 0 {
 		var backlogStatusIDsJSON sql.NullString
 		err := r.db.QueryRowContext(ctx, `
 			SELECT backlog_status_ids
 			FROM board_configurations
-			WHERE workspace_id = ?`, workspaceID).Scan(&backlogStatusIDsJSON)
-
+			WHERE `+scopeColumn+` = ?
+			ORDER BY id
+			LIMIT 1`, scopeID).Scan(&backlogStatusIDsJSON)
+		if err != nil && !errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("failed to load backlog configuration: %w", err)
+		}
 		if err == nil && backlogStatusIDsJSON.Valid && backlogStatusIDsJSON.String != "" {
 			var statusIDs []int
 			if err := json.Unmarshal([]byte(backlogStatusIDsJSON.String), &statusIDs); err != nil {

internal/services/item_crud_service.go

@@ -620,7 +620,8 @@ type BacklogParams struct {
 	OmitDescriptions bool
 }
 
-// GetBacklogItems retrieves items with non-completed statuses for a workspace/collection
+// GetBacklogItems retrieves items whose status is configured for the backlog
+// of the requested collection or workspace.
 func (s *ItemCRUDService) GetBacklogItems(params BacklogParams) ([]models.Item, int, error) {
 	return s.GetBacklogItemsContext(context.Background(), params)
 }
@@ -632,7 +633,7 @@ func (s *ItemCRUDService) GetBacklogItemsContext(ctx context.Context, params Bac
 	}
 
 	// Resolve backlog status IDs
-	backlogStatusIDs, err := s.repo.GetBacklogStatusIDsContext(ctx, params.WorkspaceID)
+	backlogStatusIDs, err := s.repo.GetBacklogStatusIDsContext(ctx, params.WorkspaceID, params.CollectionID)
 	if err != nil {
 		return nil, 0, fmt.Errorf("failed to get backlog statuses: %w", err)
 	}