feat: saved board views and richer board filters

The board now filters by text, type, priority and unassigned tickets as
well. Any combination can be saved as a named view, private or shared with
the project, and opened again with one click.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/domain/src/lib/read-models/index.ts

@@ -7,3 +7,4 @@ export * from './activity.read-model';
 export * from './project-stats.read-model';
 export * from './analytics.read-model';
 export * from './notification.read-model';
+export * from './saved-filter.read-model';

libs/api/tracker/domain/src/lib/read-models/saved-filter.read-model.ts

@@ -0,0 +1,29 @@
+import { IssuePriority } from '../issue/issue.enums';
+import { UserRefReadModel } from './user-ref.read-model';
+
+/** What a saved view of the board narrows the tickets to. Empty: everything. */
+export class SavedFilterCriteriaReadModel {
+  /** Ticket type ids of the project's settings. */
+  types?: string[];
+  areas?: string[];
+  priorities?: IssuePriority[];
+  assigneeId?: string | null;
+  unassigned?: boolean;
+  releaseId?: string | null;
+  labels?: string[];
+  search?: string | null;
+}
+
+/**
+ * A named set of board filters. Private to whoever saved it, or shared with
+ * the whole project. Preferences, not history: kept outside the event store.
+ */
+export class SavedFilterReadModel {
+  id!: string;
+  projectId!: string;
+  owner!: UserRefReadModel;
+  name!: string;
+  shared!: boolean;
+  criteria!: SavedFilterCriteriaReadModel;
+  createdAt!: string;
+}