feat(rates): multi-tier distance band entry in last-mile rate form

- tierList field type in rule-engine form dialog (add/remove rows,
  overlap + open-ended validation, From km auto-continues)
- create submits one rate row per tier sequentially
- editing a band row keeps the single From/To/value form

apps/edr-freight-api/src/migrations/3290000000000-LastMileRequestContract.ts

@@ -0,0 +1,36 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+/**
+ * Last-mile contract fields on freight.last_mile_requests: the customer-chosen
+ * delivery date, the chief-approved advance amount (held until the invoice is
+ * generated at signing time), the rate snapshot rendered into the contract,
+ * and the customer signature bookkeeping. The signed PDF and signature image
+ * live in freight.files (resource 'last_mile_requests').
+ */
+export class LastMileRequestContract3290000000000 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE freight.last_mile_requests
+        ADD COLUMN IF NOT EXISTS requested_delivery_date date,
+        ADD COLUMN IF NOT EXISTS approved_advance_amount numeric(14,2),
+        ADD COLUMN IF NOT EXISTS contract_summary jsonb,
+        ADD COLUMN IF NOT EXISTS contract_generated_at timestamptz,
+        ADD COLUMN IF NOT EXISTS customer_signed_at timestamptz,
+        ADD COLUMN IF NOT EXISTS signer_display_name varchar(160),
+        ADD COLUMN IF NOT EXISTS consent_text text
+    `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE freight.last_mile_requests
+        DROP COLUMN IF EXISTS requested_delivery_date,
+        DROP COLUMN IF EXISTS approved_advance_amount,
+        DROP COLUMN IF EXISTS contract_summary,
+        DROP COLUMN IF EXISTS contract_generated_at,
+        DROP COLUMN IF EXISTS customer_signed_at,
+        DROP COLUMN IF EXISTS signer_display_name,
+        DROP COLUMN IF EXISTS consent_text
+    `);
+  }
+}