feat: import and export tickets as CSV

Every ticket of a project can be downloaded as CSV, and a CSV exported
from TaskStream or from Jira can be imported: types, statuses, priorities
and people are matched by id or name, the rest falls back with a warning,
and parents are rebuilt. The settings page previews an import before it
creates anything.

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

libs/web/tracker/infrastructure/src/lib/tracker-infrastructure.providers.ts

@@ -14,6 +14,7 @@ import {
   SprintsGateway,
   GitGateway,
   WebhooksGateway,
+  TransferGateway,
   TrackerRealtimeGateway,
   UsersGateway,
 } from '@task-stream/web/tracker/domain';
@@ -32,6 +33,7 @@ import { GraphqlSavedFiltersGateway } from './adapters/graphql-saved-filters.gat
 import { GraphqlSprintsGateway } from './adapters/graphql-sprints.gateway';
 import { GraphqlGitGateway } from './adapters/graphql-git.gateway';
 import { GraphqlWebhooksGateway } from './adapters/graphql-webhooks.gateway';
+import { HttpTransferGateway } from './adapters/http-transfer.gateway';
 
 /** Ports → GraphQL adapters (and REST for files). */
 export function provideTrackerInfrastructure(): EnvironmentProviders {
@@ -49,5 +51,6 @@ export function provideTrackerInfrastructure(): EnvironmentProviders {
     { provide: SprintsGateway, useClass: GraphqlSprintsGateway },
     { provide: GitGateway, useClass: GraphqlGitGateway },
     { provide: WebhooksGateway, useClass: GraphqlWebhooksGateway },
+    { provide: TransferGateway, useClass: HttpTransferGateway },
   ]);
 }