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/web/tracker/domain/src/lib/ports/gateways.ts

@@ -6,6 +6,8 @@ import {
   Comment,
   Epic,
   SavedFilter,
+  Sprint,
+  SprintBurndown,
   SavedFilterCriteria,
   CommandResult,
   Issue,
@@ -32,6 +34,8 @@ import {
   MyIssuesFilter,
   UpdateIssueInput,
   UpdateProjectInput,
+  CreateSprintInput,
+  UpdateSprintInput,
 } from '../models/inputs';
 
 /*
@@ -173,6 +177,25 @@ export abstract class ReleasesGateway {
   abstract burnup(releaseId: string): Observable<ReleaseBurnup>;
 }
 
+export abstract class SprintsGateway {
+  /** With their progress: under way, planned, then closed. */
+  abstract list(projectId: string): Observable<Sprint[]>;
+  abstract burndown(sprintId: string): Observable<SprintBurndown>;
+  abstract create(input: CreateSprintInput): Observable<CommandResult>;
+  abstract update(input: UpdateSprintInput): Observable<CommandResult>;
+  abstract start(sprintId: string): Observable<CommandResult>;
+  /** Unfinished tickets go to `carryOverTo` (null: the backlog). */
+  abstract close(
+    sprintId: string,
+    carryOverTo: string | null,
+  ): Observable<CommandResult>;
+  abstract remove(sprintId: string): Observable<CommandResult>;
+  abstract setIssueSprint(
+    issueId: string,
+    sprintId: string | null,
+  ): Observable<CommandResult>;
+}
+
 export abstract class ActivityGateway {
   abstract list(projectId: string, issueId?: string): Observable<Activity[]>;
 }
@@ -219,6 +242,8 @@ export abstract class TrackerRealtimeGateway {
   abstract commentChanges(issueId: string): Observable<CommentChanged>;
   abstract activity(projectId: string): Observable<Activity>;
   abstract releaseChanges(projectId: string): Observable<Release>;
+  /** Something about a sprint of the project changed (or it was deleted). */
+  abstract sprintChanges(projectId: string): Observable<{ sprintId: string }>;
   abstract projectChanges(projectId: string): Observable<ProjectChanged>;
   abstract myProjectsChanges(): Observable<ProjectChanged>;
   abstract notifications(): Observable<Notification>;