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]+)*$/, {
+    message: "slug must be lowercase alphanumeric with hyphens",
+  })
+  slug?: string;
+
   @IsOptional()
   @IsString({ message: "color must be a string" })
   @Matches(/^#[0-9A-Fa-f]{6}$/, {

apps/api/src/knowledge/tags.service.ts

@@ -209,7 +209,19 @@ export class TagsService {
       }
     }
 
-    // Update tag
+    // Update tag - only include defined fields
+    const updateData: {
+      name?: string;
+      slug?: string;
+      color?: string | null;
+      description?: string | null;
+    } = {};
+    
+    if (updateTagDto.name !== undefined) updateData.name = updateTagDto.name;
+    if (newSlug !== undefined) updateData.slug = newSlug;
+    if (updateTagDto.color !== undefined) updateData.color = updateTagDto.color;
+    if (updateTagDto.description !== undefined) updateData.description = updateTagDto.description;
+
     const tag = await this.prisma.knowledgeTag.update({
       where: {
         workspaceId_slug: {
@@ -217,12 +229,7 @@ export class TagsService {
           slug,
         },
       },
-      data: {
-        name: updateTagDto.name,
-        slug: newSlug,
-        color: updateTagDto.color,
-        description: updateTagDto.description,
-      },
+      data: updateData,
       select: {
         id: true,
         workspaceId: true,