feat: add domains, ideas, layouts, widgets API modules

- Add DomainsModule with full CRUD, search, and activity logging
- Add IdeasModule with quick capture endpoint
- Add LayoutsModule for user dashboard layouts
- Add WidgetsModule for widget definitions (read-only)
- Update ActivityService with domain/idea logging methods
- Register all new modules in AppModule

apps/api/src/ideas/dto/query-ideas.dto.ts

@@ -0,0 +1,52 @@
+import { IdeaStatus } from "@prisma/client";
+import {
+  IsUUID,
+  IsOptional,
+  IsEnum,
+  IsInt,
+  Min,
+  Max,
+  IsString,
+} from "class-validator";
+import { Type } from "class-transformer";
+
+/**
+ * DTO for querying ideas with filters and pagination
+ */
+export class QueryIdeasDto {
+  @IsUUID("4", { message: "workspaceId must be a valid UUID" })
+  workspaceId!: string;
+
+  @IsOptional()
+  @IsEnum(IdeaStatus, { message: "status must be a valid IdeaStatus" })
+  status?: IdeaStatus;
+
+  @IsOptional()
+  @IsUUID("4", { message: "domainId must be a valid UUID" })
+  domainId?: string;
+
+  @IsOptional()
+  @IsUUID("4", { message: "projectId must be a valid UUID" })
+  projectId?: string;
+
+  @IsOptional()
+  @IsString({ message: "category must be a string" })
+  category?: string;
+
+  @IsOptional()
+  @IsString({ message: "search must be a string" })
+  search?: string;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt({ message: "page must be an integer" })
+  @Min(1, { message: "page must be at least 1" })
+  page?: number;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt({ message: "limit must be an integer" })
+  @Min(1, { message: "limit must be at least 1" })
+  @Max(100, { message: "limit must not exceed 100" })
+  limit?: number;
+}