fix(store): address Codex review findings on PR #259 (BUG-734)

Three follow-ups from Codex's review of the soft-delete filter on item-link
queries:

1. MEDIUM — GetParentMap now JOINs items on both sides and filters on
   deleted_at IS NULL. handlers_dashboard.go uses this map directly to
   detect orphaned tasks (items not present in the map are flagged), so
   without the filter a task whose parent had been soft-deleted would
   silently fail to appear as orphaned.

2. LOW — Revert the deleted_at filter on getItemLink (lowercase, private).
   Its only caller is the post-insert readback in CreateItemLink, which
   means filtering buys nothing user-facing and introduces a delete-race
   window where a successful INSERT returns nil. SetParentLink's readback
   was switched from GetItemLinks to getItemLink for the same reason.
   User-facing surfaces still go through GetItemLinks (plural) and
   GetParentForItem, both of which retain the filter.

3. LOW — Add an explicit comment in export.go documenting that item_links
   are exported in full (including links to soft-deleted items), and why
   that intentionally diverges from the user-facing query behavior.

Tests: TestGetParentMap_ExcludesSoftDeletedEndpoints exercises the
dashboard regression path on both source-side and target-side soft-delete,
plus the restore round-trip.

internal/store/export.go

@@ -97,7 +97,13 @@ func (s *Store) ExportWorkspace(slug string) (*models.WorkspaceExport, error) {
 		return nil, err
 	}
 
-	// Item links
+	// Item links — exported in full, including links whose source or target item
+	// is soft-deleted. This is intentional and differs from user-facing reads
+	// (GetItemLinks/GetParentForItem/GetParentMap, which all filter on
+	// items.deleted_at IS NULL — see BUG-734). Backups need to round-trip the
+	// raw graph so that re-importing into a workspace where the deleted items
+	// are restored preserves the original relationships. The import path
+	// already silently skips links whose endpoints are missing entirely.
 	linkRows, err := s.db.Query(s.q(`
 		SELECT id, source_id, target_id, link_type, created_by, created_at
 		FROM item_links WHERE workspace_id = ?

internal/store/items.go

@@ -987,6 +987,13 @@ func (s *Store) CreateItemLink(workspaceID string, input models.ItemLinkCreate,
 	return s.getItemLink(id)
 }
 
+// getItemLink is the unfiltered post-insert readback used by CreateItemLink to
+// hydrate the freshly-inserted row with collection/source/target metadata. It
+// intentionally does NOT filter on items.deleted_at IS NULL: the only caller
+// is the immediate readback after INSERT, and a delete race against either
+// endpoint would otherwise cause the just-successful insert to return nil
+// (Codex review on PR #259). User-facing surfaces all read links via
+// GetItemLinks (plural) or GetParentForItem, both of which DO filter.
 func (s *Store) getItemLink(id string) (*models.ItemLink, error) {
 	var link models.ItemLink
 	var createdAt string
@@ -997,15 +1004,14 @@ func (s *Store) getItemLink(id string) (*models.ItemLink, error) {
 
 	srcStatus := s.dialect.JSONExtractText("s.fields", "status")
 	tgtStatus := s.dialect.JSONExtractText("t.fields", "status")
-	// Filter out links pointing to or from soft-deleted items — see BUG-734.
 	err := s.db.QueryRow(s.q(fmt.Sprintf(`
 		SELECT l.id, l.workspace_id, l.source_id, l.target_id, l.link_type, l.created_by, l.created_at,
 		       s.title, t.title, s.slug, t.slug, sc.slug, tc.slug, sc.prefix, tc.prefix,
 		       s.item_number, t.item_number,
 		       %s, %s
 		FROM item_links l
-		JOIN items s ON s.id = l.source_id AND s.deleted_at IS NULL
-		JOIN items t ON t.id = l.target_id AND t.deleted_at IS NULL
+		JOIN items s ON s.id = l.source_id
+		JOIN items t ON t.id = l.target_id
 		JOIN collections sc ON sc.id = s.collection_id
 		JOIN collections tc ON tc.id = t.collection_id
 		WHERE l.id = ?
@@ -1172,17 +1178,10 @@ func (s *Store) SetParentLink(workspaceID, itemID, parentID, createdBy string) (
 		return nil, fmt.Errorf("commit parent link: %w", err)
 	}
 
-	// Return the full link with enriched fields
-	links, err := s.GetItemLinks(itemID)
-	if err != nil {
-		return nil, err
-	}
-	for _, link := range links {
-		if link.ID == id {
-			return &link, nil
-		}
-	}
-	return nil, fmt.Errorf("parent link created but not found")
+	// Return the full link with enriched fields. Use the unfiltered readback
+	// helper so that a delete race against either endpoint between commit and
+	// readback doesn't cause the successful insert to surface as nil.
+	return s.getItemLink(id)
 }
 
 // checkParentCycle walks the ancestor chain from parentID and returns an error
@@ -1281,10 +1280,17 @@ func (s *Store) GetParentForItem(itemID string) (*models.ItemLink, error) {
 
 // GetParentMap returns a map of item ID -> parent item ID for all parent links
 // in a workspace. Used for efficient batch lookups (e.g., dashboard, list enrichment).
+//
+// Links whose source or target item is soft-deleted are excluded so that
+// dashboard orphan-detection (handlers_dashboard.go) and similar enrichment
+// passes don't treat a task whose parent has been archived as still parented.
+// See BUG-734.
 func (s *Store) GetParentMap(workspaceID string) (map[string]string, error) {
 	rows, err := s.db.Query(s.q(fmt.Sprintf(`
-		SELECT source_id, target_id FROM item_links
-		WHERE workspace_id = ? AND link_type IN (%s)
+		SELECT il.source_id, il.target_id FROM item_links il
+		JOIN items s ON s.id = il.source_id AND s.deleted_at IS NULL
+		JOIN items t ON t.id = il.target_id AND t.deleted_at IS NULL
+		WHERE il.workspace_id = ? AND il.link_type IN (%s)
 	`, childLinkTypeSQL())), workspaceID)
 	if err != nil {
 		return nil, fmt.Errorf("get parent map: %w", err)

internal/store/items_test.go

@@ -1070,6 +1070,68 @@ func TestGetParentForItem_HidesSoftDeletedParent(t *testing.T) {
 	}
 }
 
+// TestGetParentMap_ExcludesSoftDeletedEndpoints covers the dashboard
+// orphan-detection path: a task whose parent has been soft-deleted should
+// NOT appear in GetParentMap, so handlers_dashboard.go correctly flags the
+// task as orphaned. See BUG-734 / Codex review on PR #259.
+func TestGetParentMap_ExcludesSoftDeletedEndpoints(t *testing.T) {
+	s := testStore(t)
+	ws := createTestWorkspace(t, s, "Test")
+	col := createTestCollection(t, s, ws.ID, "Tasks")
+
+	parent := createTestItem(t, s, ws.ID, col.ID, "Parent", "")
+	child := createTestItem(t, s, ws.ID, col.ID, "Child", "")
+	if _, err := s.SetParentLink(ws.ID, child.ID, parent.ID, "user"); err != nil {
+		t.Fatalf("SetParentLink: %v", err)
+	}
+
+	// Sanity: child→parent mapping present.
+	m, err := s.GetParentMap(ws.ID)
+	if err != nil {
+		t.Fatalf("GetParentMap: %v", err)
+	}
+	if m[child.ID] != parent.ID {
+		t.Fatalf("expected parent map %s→%s, got %s→%s", child.ID, parent.ID, child.ID, m[child.ID])
+	}
+
+	// Soft-delete the parent. The child must now look "parentless" so the
+	// dashboard orphan detector flags it.
+	if err := s.DeleteItem(parent.ID); err != nil {
+		t.Fatalf("DeleteItem: %v", err)
+	}
+	m, err = s.GetParentMap(ws.ID)
+	if err != nil {
+		t.Fatalf("GetParentMap after parent delete: %v", err)
+	}
+	if _, hasEntry := m[child.ID]; hasEntry {
+		t.Errorf("expected child to drop from parent map after parent soft-deleted (orphan-detection regression)")
+	}
+
+	// Restoring the parent should bring the mapping back.
+	if _, err := s.RestoreItem(parent.ID); err != nil {
+		t.Fatalf("RestoreItem: %v", err)
+	}
+	m, err = s.GetParentMap(ws.ID)
+	if err != nil {
+		t.Fatalf("GetParentMap after parent restore: %v", err)
+	}
+	if m[child.ID] != parent.ID {
+		t.Errorf("expected parent map to be restored to %s→%s, got %s→%s", child.ID, parent.ID, child.ID, m[child.ID])
+	}
+
+	// Soft-deleting the child side should also drop the entry.
+	if err := s.DeleteItem(child.ID); err != nil {
+		t.Fatalf("DeleteItem child: %v", err)
+	}
+	m, err = s.GetParentMap(ws.ID)
+	if err != nil {
+		t.Fatalf("GetParentMap after child delete: %v", err)
+	}
+	if _, hasEntry := m[child.ID]; hasEntry {
+		t.Errorf("expected child to drop from parent map after the child itself was soft-deleted")
+	}
+}
+
 func TestItemLinkDefaultType(t *testing.T) {
 	s := testStore(t)
 	ws := createTestWorkspace(t, s, "Test")