Build fixes, email preview system

src/types/invoice.ts

@@ -0,0 +1,38 @@
+export type StoredInvoiceStatus = "draft" | "sent" | "paid";
+export type EffectiveInvoiceStatus = "draft" | "sent" | "paid" | "overdue";
+
+export interface Invoice {
+  id: string;
+  invoiceNumber: string;
+  businessId: string | null;
+  clientId: string;
+  issueDate: Date;
+  dueDate: Date;
+  status: StoredInvoiceStatus;
+  totalAmount: number;
+  taxRate: number;
+  notes: string | null;
+  createdById: string;
+  createdAt: Date;
+  updatedAt: Date | null;
+}
+
+export interface InvoiceWithRelations extends Invoice {
+  client: {
+    id: string;
+    name: string;
+    email: string | null;
+  };
+  business: {
+    id: string;
+    name: string;
+    email: string | null;
+  } | null;
+  invoiceItems: Array<{
+    id: string;
+    date: Date;
+    description: string;
+    hours: number;
+    rate: number;
+  }>;
+}