feat: comments marked as decisions, on top of the ticket and searchable

Whoever can change the ticket flags a comment as a decision (new event
CommentDecisionMarkedEvent on the comment). The ticket page lists its
decisions above the description, with a link to the comment in the
conversation (`?comment=<id>` scrolls to it and points at it), and the
search palette finds them by their text across my projects.

API: markDecision / PUT-DELETE /api/comments/{id}/decision; Issue.decisions
and GET /api/issues/{issue}/decisions; decisions(projectId?, search) and
GET /api/projects/{project}/decisions, GET /api/me/decisions. MCP:
mark_decision, search_decisions, and get_issue includes them.

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

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

@@ -45,6 +45,7 @@ import {
   ChecklistItemBodyDto,
   AddCommentDto,
   CreateIssueDto,
+  DecisionsQueryDto,
   IssueSearchQueryDto,
   PresenceBodyDto,
   LinkIssueDto,
@@ -61,7 +62,9 @@ import {
   ActivityDto,
   BulkResultDto,
   CommandResultDto,
+  CommentDto,
   CommentPageDto,
+  DecisionDto,
   EpicDto,
   IssueDto,
   IssuePageDto,
@@ -707,6 +710,57 @@ export class IssuesController {
     );
   }
 
+  @Get('issues/:issue/decisions')
+  @ApiOptionalPireonAuth()
+  @ISSUE
+  @ApiOperation({
+    summary: 'Comments of the ticket marked as decisions (oldest first)',
+  })
+  @ApiOkResponse({ type: [CommentDto] })
+  @ApiReadErrors()
+  async issueDecisions(
+    @CurrentUser() me: User | undefined,
+    @Param('issue') issue: string,
+  ) {
+    return this.comments.decisions(
+      viewerOf(me),
+      await this.refs.issueId(viewerOf(me), issue),
+    );
+  }
+
+  @Get('projects/:project/decisions')
+  @ApiOptionalPireonAuth()
+  @PROJECT
+  @ApiOperation({
+    summary: "Search a project's decisions (most recent first)",
+  })
+  @ApiOkResponse({ type: [DecisionDto] })
+  @ApiReadErrors()
+  async projectDecisions(
+    @CurrentUser() me: User | undefined,
+    @Param('project') project: string,
+    @Query() query: DecisionsQueryDto,
+  ) {
+    return this.comments.searchDecisions(viewerOf(me), {
+      projectId: await this.refs.projectId(viewerOf(me), project),
+      search: query.search,
+      limit: query.limit,
+    });
+  }
+
+  @Get('me/decisions')
+  @ApiOperation({
+    summary: 'Search the decisions of all my projects (most recent first)',
+  })
+  @ApiOkResponse({ type: [DecisionDto] })
+  @ApiReadErrors()
+  myDecisions(@CurrentUser() me: User, @Query() query: DecisionsQueryDto) {
+    return this.comments.searchDecisions(me.id, {
+      search: query.search,
+      limit: query.limit,
+    });
+  }
+
   @Post('issues/:issue/comments')
   @ISSUE
   @ApiOperation({