Initial commit: ws_vatcheck at v1.0.3

Includes the fix for the GR/EL VAT prefix bug that broke exemption for
every Greek VAT number (in_array-on-values vs array_key_exists in
CacheTaxManager/VatNumber, plus the missing use import in
EuValidatorAdapter). Adds IMPROVEMENTS.txt with a checklist of features
adopted from comparing against the vatchecker module (offline-fallback
policy, failure logging, company-name check, configurable EU country
list, per-product exclusion, GB/XI mapping, AJAX live validation,
address-priority strategy).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

composer.json

@@ -0,0 +1,29 @@
+{
+    "name": "websmid/vatcheck",
+    "description": "Maakt het vrijstellen van BTW mogelijk via een gecachte vat check",
+    "authors": [
+        {
+            "name": "Johan van der Klis - De Websmid BV",
+            "email": "johan@dewebsmid.nl"
+        }
+    ],
+    "require": {
+        "ph-7/eu-vat-validator": "3.1"
+    },
+    "autoload": {
+        "psr-4": {
+            "Websmid\\VatCheck\\": "src/"
+        },
+        "classmap": [
+            "ws_vatcheck.php"
+        ],
+        "exclude-from-classmap": []
+    },
+    "config": {
+        "preferred-install": "dist",
+        "prepend-autoloader": false
+    },
+    "type": "prestashop-module",
+    "author": "Johan van der Klis - De Websmid BV",
+    "license": "MIT"
+}