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>

IMPROVEMENTS.txt

@@ -0,0 +1,66 @@
+ws_vatcheck — planned improvements
+adapted from a comparison against the "vatchecker" module (Inform-All & Keraweb), 2026-09-11
+cache TTL (1 year) explicitly kept as-is, not on this list.
+
+[ ] 1. Configurable VIES-offline fallback policy
+    - Add a setting (e.g. VATCHECK_OFFLINE_MODE) with explicit modes instead of an
+      implicit fail-closed default:
+        - always mark invalid (current implicit behavior)
+        - always mark valid
+        - reuse last cached result, fall back to invalid if none
+        - reuse last cached result, fall back to valid if none
+    - Directly related to the GR/EL bug fixed this session: the fallback behavior
+      should be an explicit, chosen policy, not an accidental side effect of
+      whether an exception happens to get caught.
+
+[ ] 2. Log every VIES check failure
+    - Currently EuValidatorAdapter::checkAndStore() has no logging at all on
+      failure (this silence was a big part of why the GR/EL bug took so long to
+      diagnose). Add PrestaShopLogger::addLog(...) (or equivalent) whenever the
+      Europa/Validator call throws, including the VAT number, country code, and
+      the fault message.
+
+[ ] 3. Company-name cross-check against VIES response
+    - When VIES returns a company name for a validated VAT number, optionally
+      compare it (normalized: lowercase, strip punctuation/legal-entity suffixes
+      like bv/gmbh/ltd/nv/sa) against the address's company field. Make this
+      togglable, since not all member states return a name.
+
+[ ] 4. Configurable EU country allow-list
+    - Replace hardcoded VatNumber::$euIso-driven behavior with an admin-configurable
+      list of which EU countries are allowed to order VAT-free, similar to
+      vatchecker's VATCHECKER_EU_COUNTRIES setting.
+
+[ ] 5. Per-product VAT exclusion
+    - Some products (e.g. certain digital services) may need to always charge VAT
+      regardless of customer VAT-exempt status. Add a product-level flag/table
+      (mirroring vatchecker_excluded_products) and consult it before applying the
+      0% tax manager for a given product line.
+
+[ ] 6. GB -> XI (Northern Ireland) mapping
+    - VatNumber::$euIso has no entry at all for the UK/Northern Ireland. If this
+      shop (or any future ws_vatcheck deployment) ships to Northern Ireland with an
+      XI-prefixed VAT number, it will hit the same class of key/value bug already
+      fixed for Greece. Add the mapping and cover it with the same key-based checks.
+
+[ ] 7. Front-end AJAX live VAT validation
+    - Add an AJAX front controller + JS so the address form validates the VAT
+      number as the customer types, instead of only on form submit
+      (hookActionValidateCustomerAddressForm). Mirrors vatchecker's ajax.php +
+      front.js/front.css pattern. Improves UX and surfaces bad VAT numbers earlier.
+
+[ ] 8. Configurable address-priority strategy
+    - Add a setting for which address's VAT number is authoritative when invoice
+      and delivery addresses differ (shipping only / invoice only / prioritize
+      invoice / prioritize shipping), instead of relying on implicit PS tax-address
+      resolution. Mirrors vatchecker's VATCHECKER_ADDRESS_SELECT.
+
+Explicitly deferred / not adopting:
+- Shortening the 1-year cache TTL (Config::CACHE_VALIDITY) — decided to leave as-is.
+- Class overrides (Carrier/Product) as used by vatchecker — do not port this pattern;
+  it conflicts with other modules that override the same core classes and is fragile
+  across PS core upgrades. If shipping/product tax rule assignment ever needs
+  behavior beyond what the taxManager hook covers, investigate a hook-based solution
+  first before reaching for an override.
+- Legacy $this->l() / translations/{iso}.php system — ws_vatcheck already uses
+  $this->trans() correctly per house convention for PS >= 1.7.6.0.