feat: an ordered backlog

A Backlog tab lists the tickets still to start in the order the team will
take them; drag them, or use the arrows, to reorder. Moving a ticket only
rewrites that ticket's rank, read from the event store, and board columns
follow the same order.

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

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

@@ -12,6 +12,7 @@ import {
   StatusCategory,
   TYPE_ICONS,
 } from '@task-stream/api/tracker/domain';
+import { IssueSort } from '@task-stream/api/tracker/application';
 import { Transform, Type } from 'class-transformer';
 import {
   ArrayMaxSize,
@@ -416,6 +417,15 @@ export class IssueSearchQueryDto extends PageQueryDto {
   @IsString()
   parent?: string;
 
+  @ApiPropertyOptional({
+    enum: IssueSort,
+    enumName: 'IssueSort',
+    description: 'RECENT (default): last updated first. RANK: backlog order.',
+  })
+  @IsOptional()
+  @IsEnum(IssueSort)
+  sort?: IssueSort;
+
   @ApiPropertyOptional({ description: 'Matches key, title or description' })
   @IsOptional()
   @IsString()
@@ -579,6 +589,30 @@ export class SetIssueReleaseDto {
   releaseId!: string | null;
 }
 
+export class RankIssueDto {
+  @ApiPropertyOptional({
+    type: String,
+    nullable: true,
+    example: 'WEB-4',
+    description:
+      'The ticket that ends up right above (id or key; null: the top)',
+  })
+  @IsOptional()
+  @IsString()
+  above?: string | null;
+
+  @ApiPropertyOptional({
+    type: String,
+    nullable: true,
+    example: 'WEB-9',
+    description:
+      'The ticket that ends up right below (id or key; null: the bottom)',
+  })
+  @IsOptional()
+  @IsString()
+  below?: string | null;
+}
+
 export class SetIssueParentDto {
   @ApiProperty({
     type: String,

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

@@ -179,6 +179,11 @@ export class IssueDto {
     description: 'The epic or ticket this one breaks down',
   })
   parent!: IssueParentDto | null;
+  @ApiProperty({
+    description:
+      'Place in the backlog and its board column (ascending, as text)',
+  })
+  rank!: string;
   @ApiProperty({ type: [ChecklistItemDto] }) checklist!: ChecklistItemDto[];
   @ApiProperty() commentCount!: number;
   @ApiProperty({ format: 'date-time' }) createdAt!: string;