Implement economic config round-trip test and enhance department handling

- Added a test to ensure correct round-tripping of default distribution department config value through economic config updates.
- Improved department handling by adding fallback logic to use the default economic distribution department id when a customer's department id is missing.
- Enhanced weather API routes to fetch, cache, and return detailed employee contributions per department for a given time slot.

openapi.yaml

@@ -2204,6 +2204,8 @@ paths:
                               transaction_draft_customer_number:
                                 type: integer
                                 nullable: true
+                              default_distribution_department_id:
+                                type: integer
                             additionalProperties: false
                         additionalProperties: true
         '400':
@@ -12536,7 +12538,7 @@ components:
       type: object
       properties:
         module: { type: string, enum: [economic] }
-        variable: { type: string, enum: [adminFeeMonthly, adminFeeOrder, feeProductId, invoiceLayoutNumber, paymentTermsNumber, transactionDraftCustomerNumber] }
+        variable: { type: string, enum: [adminFeeMonthly, adminFeeOrder, feeProductId, invoiceLayoutNumber, paymentTermsNumber, transactionDraftCustomerNumber, defaultDepartmentId] }
         type: { type: string, enum: [string, int] }
         value:
           oneOf: