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/comments.controller.ts

@@ -6,6 +6,7 @@ import {
   Param,
   Patch,
   Post,
+  Put,
 } from '@nestjs/common';
 import { ApiOkResponse, ApiOperation, ApiTags } from '@nestjs/swagger';
 import { User } from '@task-stream/api/identity/domain';
@@ -54,6 +55,29 @@ export class CommentsController {
     return this.comments.react(me.id, commentId, body.emoji, body.on);
   }
 
+  @Put(':commentId/decision')
+  @ApiOperation({
+    summary: 'Mark a comment as a decision of its ticket',
+    description:
+      'Whoever can change the ticket. Decisions are shown above the ticket and searchable (GET …/decisions).',
+  })
+  @ApiOkResponse({ type: CommandResultDto })
+  @ApiCommandErrors()
+  markDecision(@CurrentUser() me: User, @Param('commentId') commentId: string) {
+    return this.comments.markDecision(me.id, commentId, true);
+  }
+
+  @Delete(':commentId/decision')
+  @ApiOperation({ summary: 'It is no longer a decision' })
+  @ApiOkResponse({ type: CommandResultDto })
+  @ApiCommandErrors()
+  unmarkDecision(
+    @CurrentUser() me: User,
+    @Param('commentId') commentId: string,
+  ) {
+    return this.comments.markDecision(me.id, commentId, false);
+  }
+
   @Delete(':commentId')
   @ApiOperation({ summary: 'Delete a comment (author or project admin)' })
   @ApiOkResponse({ type: CommandResultDto })

libs/api/tracker/presenters/src/lib/http/dto/requests.dto.ts

@@ -501,6 +501,22 @@ export class PageQueryDto {
   offset = 0;
 }
 
+export class DecisionsQueryDto {
+  @ApiPropertyOptional({ description: 'Words in the decision' })
+  @IsOptional()
+  @IsString()
+  @MaxLength(200)
+  search?: string;
+
+  @ApiPropertyOptional({ type: Number, default: 20, minimum: 1, maximum: 100 })
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  @Min(1)
+  @Max(100)
+  limit = 20;
+}
+
 // ---- Issues -----------------------------------------------------------------
 
 export class MyIssuesQueryDto extends PageQueryDto {

libs/api/tracker/presenters/src/lib/http/dto/responses.dto.ts

@@ -625,12 +625,30 @@ export class CommentDto {
     description: 'In the order they are offered; only the ones somebody chose',
   })
   reactions!: CommentReactionDto[];
+  @ApiProperty({
+    description: 'Marked as a decision of the ticket (shown above it)',
+  })
+  decision!: boolean;
+  @ApiProperty({
+    type: UserRefDto,
+    nullable: true,
+    description: 'Who marked it as a decision',
+  })
+  decidedBy!: UserRefDto | null;
+  @ApiProperty({ type: String, nullable: true, format: 'date-time' })
+  decidedAt!: string | null;
   @ApiProperty({ format: 'date-time' }) createdAt!: string;
   @ApiProperty({ type: String, nullable: true, format: 'date-time' })
   editedAt!: string | null;
   @ApiProperty() version!: number;
 }
 
+/** A comment marked as a decision, with its ticket. */
+export class DecisionDto {
+  @ApiProperty({ type: CommentDto }) comment!: CommentDto;
+  @ApiProperty({ type: IssueParentDto }) issue!: IssueParentDto;
+}
+
 export class CommentPageDto {
   @ApiProperty({ type: [CommentDto] }) items!: CommentDto[];
   @ApiProperty() total!: number;

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({