feat: notifications in the app and, optionally, by e-mail

Derived from events and kept per person: whoever a ticket is assigned to,
whoever reports or works on it when it moves, fails QA or gets a comment,
and whoever joins a project. Never about what you did yourself, once per
event. They arrive live through a subscription to a bell in the header,
and are copied by e-mail to whoever turns it on when SMTP_URL is set.

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

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

@@ -637,3 +637,39 @@ export class PublishReleaseDto {
   @IsBoolean()
   force = false;
 }
+
+// ---- Notifications ----------------------------------------------------------
+
+export class MyNotificationsQueryDto {
+  @ApiPropertyOptional({ default: false, description: 'Only unread ones' })
+  @IsOptional()
+  @Transform(toBoolean)
+  @IsBoolean()
+  unreadOnly = false;
+
+  @ApiPropertyOptional({ type: Number, default: 30, minimum: 1, maximum: 100 })
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  @Min(1)
+  @Max(100)
+  limit = 30;
+}
+
+export class MarkNotificationsReadDto {
+  @ApiPropertyOptional({
+    type: [String],
+    description: 'Omit to mark all of them',
+  })
+  @IsOptional()
+  @IsArray()
+  @ArrayMaxSize(200)
+  @IsString({ each: true })
+  ids?: string[];
+}
+
+export class NotificationSettingsDto {
+  @ApiProperty({ description: 'Copies by e-mail' })
+  @IsBoolean()
+  email!: boolean;
+}