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';