Fix state code resolution at shipment time + fix INT.XP fallback

- Resolve full state names (e.g. California -> CA) in createShipment XML
  so existing orders with full names in DB are handled
- Only fall back to INT.XP when CP_CONTRACT_ID is set (it requires a contract)
- Include error details in 502 response

Author: jeninh

resolution-frontend/src/lib/server/canada-post.ts

@@ -2,6 +2,7 @@ import { env } from '$env/dynamic/private';
 import xml2js from 'xml2js';
 import { PDFDocument } from 'pdf-lib';
 import { fetchChitChatsRates } from './chit-chats';
+import { resolveStateCode } from './countries';
 
 export const INCHES_TO_CM = 2.54;
 export const GRAMS_TO_KG = 0.001;
@@ -194,7 +195,7 @@ export function buildCreateShipmentXml(params: {
 				<address-line-1>${escapeXml((order.addressLine1 || '').substring(0, 44))}</address-line-1>
 				${(order.addressLine2 || order.addressLine1?.length > 44) ? `<address-line-2>${escapeXml((order.addressLine2 || order.addressLine1?.substring(44) || '').substring(0, 44))}</address-line-2>` : ''}
 				<city>${escapeXml((order.city || '').substring(0, 40))}</city>
-				<prov-state>${escapeXml((order.stateProvince || '').substring(0, 20))}</prov-state>
+				<prov-state>${escapeXml(resolveStateCode(order.stateProvince || '').substring(0, 20))}</prov-state>
 				<country-code>${escapeXml(order.country)}</country-code>
 				<postal-zip-code>${(order.postalCode ?? '').replace(/\s/g, '').toUpperCase()}</postal-zip-code>
 			</address-details>

resolution-frontend/src/routes/api/fulfillment/get-label/+server.ts

@@ -231,7 +231,10 @@ export const POST: RequestHandler = async ({ request, locals }) => {
 		console.log(`Creating shipment: country=${order.country}, estimatedService=${order.estimatedServiceName}, serviceCode=${serviceCode}`);
 
 		// Try creating shipment, fall back to alternate international services if unavailable
-		const fallbackCodes = serviceCode === 'INT.TP' ? ['INT.XP'] : serviceCode === 'INT.XP' ? ['INT.TP'] : [];
+		// INT.XP requires a contract, so only use it as fallback when contract is available
+		const fallbackCodes: string[] = [];
+		if (serviceCode === 'INT.TP' && env.CP_CONTRACT_ID) fallbackCodes.push('INT.XP');
+		if (serviceCode === 'INT.XP') fallbackCodes.push('INT.TP');
 		let lastError: any;
 		for (const code of [serviceCode, ...fallbackCodes]) {
 			try {
@@ -247,7 +250,7 @@ export const POST: RequestHandler = async ({ request, locals }) => {
 			}
 		}
 		if (lastError) {
-			throw error(502, `Canada Post shipment creation failed`);
+			throw error(502, `Canada Post shipment creation failed: ${lastError.message}`);
 		}
 	}