feat: «Mi día», the few tickets I pick for today

A home panel with the tickets picked for today (10 at most), crossed out
as they get done and counted («1 de 3 terminados»), my open tickets to
add with one click, and what was left unfinished on my last day to carry
over. «☀ Mi día» on a ticket adds it or takes it out. The day is the
person's own (YYYY-MM-DD from the browser); private, no history (Mongo
`my_days`).

API: myDay(day), addToMyDay, removeFromMyDay; GET /api/me/day,
PUT/DELETE /api/me/day/{issue}. MCP: my_day.

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

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

@@ -1427,3 +1427,15 @@ export class ReminderOnIssueDto {
   @ApiProperty({ type: IssueReminderDto }) reminder!: IssueReminderDto;
   @ApiProperty({ type: () => IssueDto }) issue!: IssueDto;
 }
+
+export class MyDayLeftoverDto {
+  @ApiProperty() day!: string;
+  @ApiProperty({ type: () => [IssueDto] }) issues!: IssueDto[];
+}
+
+export class MyDayDto {
+  @ApiProperty({ description: 'YYYY-MM-DD, in my time zone' }) day!: string;
+  @ApiProperty({ type: () => [IssueDto] }) issues!: IssueDto[];
+  @ApiProperty({ type: MyDayLeftoverDto, nullable: true })
+  leftover!: MyDayLeftoverDto | null;
+}