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/layouts/dto/create-layout.dto.ts

@@ -0,0 +1,31 @@
+import {
+  IsString,
+  IsOptional,
+  IsBoolean,
+  IsArray,
+  MinLength,
+  MaxLength,
+  IsObject,
+} from "class-validator";
+import { Layout } from "../types/widget.types";
+
+/**
+ * DTO for creating a new user layout
+ */
+export class CreateLayoutDto {
+  @IsString({ message: "name must be a string" })
+  @MinLength(1, { message: "name must not be empty" })
+  @MaxLength(100, { message: "name must not exceed 100 characters" })
+  name!: string;
+
+  @IsOptional()
+  @IsBoolean({ message: "isDefault must be a boolean" })
+  isDefault?: boolean;
+
+  @IsArray({ message: "layout must be an array" })
+  layout!: Layout;
+
+  @IsOptional()
+  @IsObject({ message: "metadata must be an object" })
+  metadata?: Record<string, unknown>;
+}

apps/api/src/layouts/dto/index.ts

@@ -0,0 +1,2 @@
+export { CreateLayoutDto } from "./create-layout.dto";
+export { UpdateLayoutDto } from "./update-layout.dto";

apps/api/src/layouts/dto/update-layout.dto.ts

@@ -0,0 +1,34 @@
+import {
+  IsString,
+  IsOptional,
+  IsBoolean,
+  IsArray,
+  MinLength,
+  MaxLength,
+  IsObject,
+} from "class-validator";
+import { Layout } from "../types/widget.types";
+
+/**
+ * DTO for updating an existing user layout
+ * All fields are optional to support partial updates
+ */
+export class UpdateLayoutDto {
+  @IsOptional()
+  @IsString({ message: "name must be a string" })
+  @MinLength(1, { message: "name must not be empty" })
+  @MaxLength(100, { message: "name must not exceed 100 characters" })
+  name?: string;
+
+  @IsOptional()
+  @IsBoolean({ message: "isDefault must be a boolean" })
+  isDefault?: boolean;
+
+  @IsOptional()
+  @IsArray({ message: "layout must be an array" })
+  layout?: Layout;
+
+  @IsOptional()
+  @IsObject({ message: "metadata must be an object" })
+  metadata?: Record<string, unknown>;
+}