feat(task-005): complete article intake dashboard detail flow

apps/frontend/src/features/article-intake/model.ts

@@ -0,0 +1,43 @@
+import type { TargetSiteConfig } from "@pipeline/shared";
+
+export type NewArticleDraft = {
+  targetSiteId: string;
+  briefDescription: string;
+  workingTitle: string;
+  contentType: string;
+  primaryKeyword: string;
+};
+
+export type FieldErrors = Record<string, string>;
+
+export type NewArticleFormState = {
+  values: NewArticleDraft;
+  errors: FieldErrors;
+  formError?: string;
+};
+
+export function initialDraft(sites: readonly TargetSiteConfig[]): NewArticleDraft {
+  return {
+    targetSiteId: sites.length > 0 ? sites[0].id : "",
+    briefDescription: "",
+    workingTitle: "",
+    contentType: "longform_guide",
+    primaryKeyword: "",
+  };
+}
+
+export function validateArticleDraft(values: NewArticleDraft): FieldErrors {
+  const errors: FieldErrors = {};
+
+  if (!values.targetSiteId) {
+    errors.targetSiteId = "Select a target site";
+  }
+  if (!values.briefDescription.trim()) {
+    errors.briefDescription = "Brief description is required";
+  }
+  if (!values.contentType.trim()) {
+    errors.contentType = "Content type is required";
+  }
+
+  return errors;
+}