fix(knowledge): resolve TypeScript errors in tags service

- Fix updateData typing for partial updates
- Add slug field to CreateTagDto
- Build now passes

Note: tasks.controller.spec.ts needs test config update for WorkspaceGuard

apps/api/src/knowledge/dto/create-tag.dto.ts

@@ -15,6 +15,13 @@ export class CreateTagDto {
   @MaxLength(100, { message: "name must not exceed 100 characters" })
   name!: string;
 
+  @IsOptional()
+  @IsString({ message: "slug must be a string" })
+  @Matches(/^[a-z0-9]+(?:-[a-z0-9]+)*$/, {
+    message: "slug must be lowercase alphanumeric with hyphens",
+  })
+  slug?: string;
+
   @IsOptional()
   @IsString({ message: "color must be a string" })
   @Matches(/^#[0-9A-Fa-f]{6}$/, {