feat: sprints with burndown and carry-over

Plan sprints with dates and a goal, run one at a time per project, and
put tickets in them from the ticket page. The Sprints tab follows the one
under way with its progress and a burndown in tickets or points against
the ideal line. Closing a sprint sends what was left to the next one or
back to the backlog; the board can be filtered by sprint.

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

libs/api/tracker/application/src/lib/event-handlers/event-handlers.ts

@@ -31,6 +31,8 @@ import { IssueWatchersEventHandler } from './issue-watchers.event-handler';
 import { IssueParentChangedEventHandler } from './issue-parent-changed.event-handler';
 import { IssueChecklistEventHandler } from './issue-checklist.event-handler';
 import { IssueRankedEventHandler } from './issue-ranked.event-handler';
+import { SprintEventHandler } from './sprint.event-handler';
+import { IssueSprintChangedEventHandler } from './issue-sprint-changed.event-handler';
 
 /** Read-model projections (MongoDB) + realtime, fed by the EventsBridge. */
 export const EVENT_HANDLERS = [
@@ -66,6 +68,8 @@ export const EVENT_HANDLERS = [
   IssueParentChangedEventHandler,
   IssueChecklistEventHandler,
   IssueRankedEventHandler,
+  SprintEventHandler,
+  IssueSprintChangedEventHandler,
 ];
 
 export { ReadModelNotifier };