feat: resolve outcodes from local DB before HTTP

app/Services/PostcodeService.php

@@ -2,6 +2,7 @@
 
 namespace App\Services;
 
+use App\Models\Outcode;
 use App\Models\Postcode;
 use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\Http;
@@ -35,7 +36,7 @@ class PostcodeService
 
         $result = match (true) {
             $this->isFullPostcode($query) => $this->lookupLocalPostcode($query) ?? $this->lookupPostcode($query),
-            $this->isOutcode($query) => $this->lookupOutcode($query),
+            $this->isOutcode($query) => $this->lookupLocalOutcode($query) ?? $this->lookupOutcode($query),
             default => $this->lookupPlace($query),
         };
 
@@ -74,6 +75,24 @@ class PostcodeService
         );
     }
 
+    private function lookupLocalOutcode(string $outcode): ?LocationResult
+    {
+        $normalised = strtoupper(trim($outcode));
+
+        $row = Outcode::find($normalised);
+
+        if ($row === null) {
+            return null;
+        }
+
+        return new LocationResult(
+            query: $outcode,
+            displayName: $normalised,
+            lat: $row->lat,
+            lng: $row->lng,
+        );
+    }
+
     private function formatPostcode(string $normalised): string
     {
         // Insert the single space before the last 3 chars ("SW1A1AA" -> "SW1A 1AA").