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/graphql/inputs.ts

@@ -5,6 +5,7 @@ import {
   ProjectRole,
   StatusCategory,
 } from '@task-stream/api/tracker/domain';
+import { IssueSort } from '@task-stream/api/tracker/application';
 import { Type } from 'class-transformer';
 import {
   ArrayMaxSize,
@@ -180,6 +181,25 @@ export class ChangeIssueStatusInput {
   reason?: string | null;
 }
 
+@InputType()
+export class RankIssueInput {
+  @Field(() => ID) @IsUUID() issueId!: string;
+  @Field(() => ID, {
+    nullable: true,
+    description: 'The ticket that ends up right above (null: the top)',
+  })
+  @IsOptional()
+  @IsUUID()
+  aboveIssueId?: string | null;
+  @Field(() => ID, {
+    nullable: true,
+    description: 'The ticket that ends up right below (null: the bottom)',
+  })
+  @IsOptional()
+  @IsUUID()
+  belowIssueId?: string | null;
+}
+
 @InputType()
 export class AddChecklistItemInput {
   @Field(() => ID) @IsUUID() issueId!: string;
@@ -249,6 +269,10 @@ export class IssueFilterInput {
   @IsOptional()
   @IsUUID()
   parentId?: string;
+  @Field(() => IssueSort, { nullable: true, defaultValue: IssueSort.RECENT })
+  @IsOptional()
+  @IsEnum(IssueSort)
+  sort?: IssueSort;
   @Field({ nullable: true, description: 'Matches key, title or description' })
   @IsOptional()
   @IsString()