Feature: Add ACS courier integration

ACS rate driver (live price quotes via ACS_Price_Calculation, cached postcode-to-station lookups) and fulfillment service (voucher creation, label printing, end-of-day pickup manifest). Adds a per-rate pricing_mode column so admins can choose live API pricing vs. a fixed price on ACS-driven shipping rates, surfaced via a custom Rates page.

src/Shipping/Carriers/Acs/AcsResponse.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Modules\Core\Shipping\Carriers\Acs;
+
+use Illuminate\Http\Client\Response;
+use Modules\Core\Shipping\Carriers\Acs\Exceptions\AcsApiException;
+
+class AcsResponse
+{
+    private function __construct(
+        public readonly bool $hasError,
+        public readonly ?string $errorMessage,
+        public readonly array $valueOutput,
+        public readonly array $tableOutput,
+    ) {}
+
+    public static function fromHttpResponse(Response $response): self
+    {
+        $body = $response->json() ?? [];
+
+        // ACS's own JSON key is misspelled ("Responce") — preserved here verbatim.
+        $output = $body['ACSOutputResponce'] ?? [];
+
+        return new self(
+            hasError: (bool) ($body['ACSExecution_HasError'] ?? ! $response->successful()),
+            errorMessage: $body['ACSExecutionErrorMessage'] ?? null,
+            valueOutput: $output['ACSValueOutput'][0] ?? [],
+            tableOutput: $output['ACSTableOutput'] ?? [],
+        );
+    }
+
+    public function throwIfError(): self
+    {
+        if ($this->hasError) {
+            throw new AcsApiException(
+                $this->errorMessage ?? ($this->valueOutput['Error_Message'] ?? 'Unknown ACS API error'),
+                $this->tableOutput,
+            );
+        }
+
+        return $this;
+    }
+}