feat: implement shipping line bookings management

- Add ShippingLineBookingsPage for listing and managing shipping line bookings.
- Create ShippingLineDocumentsModal for document uploads related to bookings.
- Introduce ShippingLineInitiateModal for initiating new shipping line bookings.
- Implement booking document state management with booking-doc-state utility.
- Add shipping line bookings service for API interactions.
- Update index to export new components and services.
- Enhance types for freight to include shipping line credits.

apps/edr-freight-api/src/modules/billing/entities/invoice.entity.ts

@@ -23,22 +23,37 @@ export class Invoice extends BaseEntity {
   @Column({ name: "invoice_number", type: "varchar", length: 64, unique: true })
   invoiceNumber!: string;
 
-  /** The customer (company) this invoice is billed to. */
-  @Column({ name: "company_id", type: "uuid" })
-  companyId!: string;
+  /**
+   * The customer (company) this invoice is billed to. Null on a shipping-line
+   * invoice, which is billed to `shippingLineCompanyId` instead — a shipping
+   * line is deliberately not a `companies` row. A DB CHECK
+   * (`chk_invoices_single_payer`) guarantees exactly one of the two is set.
+   */
+  @Column({ name: "company_id", type: "uuid", nullable: true })
+  companyId!: string | null;
 
   @ManyToOne(() => Company)
   @JoinColumn({ name: "company_id" })
   company?: Company;
 
   /** The specific company profile (importer/exporter/forwarder/...) billed. */
-  @Column({ name: "company_profile_id", type: "uuid" })
-  companyProfileId!: string;
+  @Column({ name: "company_profile_id", type: "uuid", nullable: true })
+  companyProfileId!: string | null;
 
   @ManyToOne(() => CompanyProfile)
   @JoinColumn({ name: "company_profile_id" })
   companyProfile?: CompanyProfile;
 
+  /**
+   * The shipping line billed, when this invoice bills batched shipping-line
+   * credits rather than a customer booking. Mutually exclusive with
+   * `companyId`. No relation is declared: `ShippingLineCredit` already owns
+   * that edge, and importing the shipping-lines module here would close an
+   * import cycle (shipping-lines already depends on billing).
+   */
+  @Column({ name: "shipping_line_company_id", type: "uuid", nullable: true })
+  shippingLineCompanyId?: string | null;
+
   /** Sum of line amounts before tax; defaults to `totalAmount` for tax-free invoices. */
   @Column({ name: "subtotal_amount", type: "numeric", precision: 14, scale: 2, default: 0 })
   subtotalAmount!: number;