feat: pinned tickets, at hand on the home page and in search

Each person pins up to 20 tickets from the ticket's page («Fijar»). They
show as a strip under the projects on the home page and in the search
palette before typing. Private and without history, like the views of
«my work» (Mongo `pinned_issues`); tickets in the trash or out of reach
are left out, and when the list is full the unreadable ones are dropped
first.

API: GET /api/me/pins, PUT/DELETE /api/issues/{issue}/pin; GraphQL
myPins, pinIssue, unpinIssue and Issue.pinned.

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

libs/api/tracker/presenters/src/lib/http/issues.controller.ts

@@ -32,6 +32,7 @@ import {
 import {
   CommentsService,
   IssuesService,
+  PinsService,
   PresenceService,
   ProjectsService,
 } from '@task-stream/api/tracker/application';
@@ -94,6 +95,7 @@ export class IssuesController {
     private readonly refs: Refs,
     private readonly presence: PresenceService,
     private readonly projects: ProjectsService,
+    private readonly pins: PinsService,
   ) {}
 
   @Get('me/home')
@@ -163,6 +165,41 @@ export class IssuesController {
     await this.presence.leave(me.id, await this.refs.issueId(me.id, issue));
   }
 
+  @Get('me/pins')
+  @ApiOperation({
+    summary: 'My pinned tickets, most recently pinned first',
+    description:
+      'Across my projects; tickets in the trash or out of my reach are left out.',
+  })
+  @ApiOkResponse({ type: [IssueDto] })
+  @ApiReadErrors()
+  async myPins(@CurrentUser() me: User) {
+    return this.refs.issueDtos(await this.pins.mine(me.id), viewerOf(me));
+  }
+
+  @Put('issues/:issue/pin')
+  @HttpCode(204)
+  @ISSUE
+  @ApiOperation({
+    summary: 'Pin a ticket: keep it at hand on my home page and in search',
+    description: 'Private to me; at most 20. Pinning it again changes nothing.',
+  })
+  @ApiNoContentResponse()
+  @ApiCommandErrors()
+  async pin(@CurrentUser() me: User, @Param('issue') issue: string) {
+    await this.pins.pin(me.id, await this.refs.issueId(me.id, issue), true);
+  }
+
+  @Delete('issues/:issue/pin')
+  @HttpCode(204)
+  @ISSUE
+  @ApiOperation({ summary: 'Unpin a ticket' })
+  @ApiNoContentResponse()
+  @ApiCommandErrors()
+  async unpin(@CurrentUser() me: User, @Param('issue') issue: string) {
+    await this.pins.pin(me.id, await this.refs.issueId(me.id, issue), false);
+  }
+
   @Put('issues/:issue/watch')
   @ISSUE
   @ApiOperation({