feat(bookings): add ad-hoc additional-charge module

New freight.additional_charge table, independent of BookingClearanceCharge
(unbounded per booking, free-text reason). Draft -> send issues an invoice
and notifies the customer in-app/SMS/email; settles via the standard
.invoice.paid event. Adds the Additional charges row-menu entry
next to Cancel booking, permission-gated.

Not included: the Additional Payments tab UI, add-charge modal, portal pay
flow.

packages/types/src/freight/index.ts

@@ -200,6 +200,11 @@ export enum InvoiceSource {
    * per-booking link.
    */
   ShippingLineCredit = "shipping_line_credit",
+  /**
+   * Ad-hoc extra charge finance raises against a booking (e.g. a fee not
+   * covered by an existing fee rule). `sourceId` is the charge id.
+   */
+  AdditionalCharge = "additional_charge",
 }
 
 export enum SchedulingStatus {
@@ -865,6 +870,36 @@ export interface ClearanceDocRequest {
   at: string;
 }
 
+// ── Additional charges (ad-hoc finance billing) ──────────────────────────────
+
+/**
+ * DRAFT: staff is still editing, nothing sent. SENT: invoice issued to the
+ * customer (in-app + SMS + email). PAID: the invoice settled. CANCELLED:
+ * withdrawn before payment.
+ */
+export type AdditionalChargeStatus = "DRAFT" | "SENT" | "PAID" | "CANCELLED";
+
+/** One ad-hoc extra charge finance raised against a booking. */
+export interface AdditionalCharge {
+  id: string;
+  bookingId: string;
+  reason: string;
+  status: AdditionalChargeStatus;
+  amount: number;
+  currency: string;
+  file: { id: string; name: string; url: string } | null;
+  invoiceId: string | null;
+  invoiceNumber: string | null;
+  paymentReference: string | null;
+  createdByName: string | null;
+  createdAt: string;
+  sentByName: string | null;
+  sentAt: string | null;
+  paidAt: string | null;
+  cancelledAt: string | null;
+  cancelReason: string | null;
+}
+
 /** One entry of a clearance document's audit trail, oldest first. */
 export interface ClearanceDocumentEvent {
   type: "UPLOADED" | "RESUBMITTED" | "QUERIED" | "APPROVED";