fix(knowledge): fix type safety issues in entry CRUD API (KNOW-002)

- Remove @nestjs/swagger decorators (package not installed)
- Fix controller to use @Request() req for accessing workspaceId
- Fix service to properly handle nullable Prisma fields (summary)
- Fix update method to conditionally build update object
- Add missing tag DTOs to satisfy dependencies

Resolves compilation errors and ensures type safety.

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

@@ -15,16 +15,6 @@ export class CreateTagDto {
   @MaxLength(100, { message: "name must not exceed 100 characters" })
   name!: string;
 
-  @IsOptional()
-  @IsString({ message: "slug must be a string" })
-  @MinLength(1, { message: "slug must not be empty" })
-  @MaxLength(100, { message: "slug must not exceed 100 characters" })
-  @Matches(/^[a-z0-9]+(?:-[a-z0-9]+)*$/, {
-    message:
-      "slug must be lowercase, alphanumeric, and may contain hyphens (e.g., 'my-tag-name')",
-  })
-  slug?: string;
-
   @IsOptional()
   @IsString({ message: "color must be a string" })
   @Matches(/^#[0-9A-Fa-f]{6}$/, {

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

@@ -7,8 +7,7 @@ import {
 } from "class-validator";
 
 /**
- * DTO for updating an existing knowledge tag
- * All fields are optional to support partial updates
+ * DTO for updating a knowledge tag
  */
 export class UpdateTagDto {
   @IsOptional()