fix(i18n): restore validation messages masked by duplicate top-level lang key [3.x] (#144)

* fix(i18n): consolidate validation messages into reusable translation keys

* test(i18n): detect duplicate top-level keys in lang files

PHP silently keeps only the last duplicate array key, which can mask
entire blocks of translations. The previous duplicate `'validation'`
key wiped out 200+ entries (including `unique_value`) and existing
key-existence tests didn't catch it because none of the listed keys
happened to live in the masked block.

Adds a structural assertion across every `resources/lang/<locale>/*.php`
file so future duplicates fail fast.

Author: ManukMinasyan

resources/lang/en/custom-fields.php

@@ -353,6 +353,17 @@
         'parameter_missing' => 'This validation rule requires exactly :count parameter(s). Please add all required parameters.',
         'invalid_rule_for_field_type' => 'The selected rule is not valid for this field type.',
         'unique_value' => 'The value ":value" is already assigned to another record.',
+        'min_length' => 'Minimum Length',
+        'max_length' => 'Maximum Length',
+        'min_value' => 'Minimum Value',
+        'max_value' => 'Maximum Value',
+        'min_selections' => 'Minimum Selections',
+        'max_selections' => 'Maximum Selections',
+        'max_file_size_kb' => 'Maximum File Size (KB)',
+        'accepted_file_types' => 'Accepted File Types',
+        'accepted_file_types_placeholder' => 'e.g. image/png, application/pdf',
+        'decimal_places' => 'Decimal Places',
+        'decimal_places_placeholder' => 'Enter a value between 0 and 4',
     ],
 
     'empty_states' => [
@@ -541,20 +552,6 @@
         'tags_input' => 'Tags Input',
     ],
 
-    'validation' => [
-        'min_length' => 'Minimum Length',
-        'max_length' => 'Maximum Length',
-        'min_value' => 'Minimum Value',
-        'max_value' => 'Maximum Value',
-        'min_selections' => 'Minimum Selections',
-        'max_selections' => 'Maximum Selections',
-        'max_file_size_kb' => 'Maximum File Size (KB)',
-        'accepted_file_types' => 'Accepted File Types',
-        'accepted_file_types_placeholder' => 'e.g. image/png, application/pdf',
-        'decimal_places' => 'Decimal Places',
-        'decimal_places_placeholder' => 'Enter a value between 0 and 4',
-    ],
-
     'currency' => [
         'fieldset' => 'Currency Settings',
         'currency' => 'Currency',

tests/Feature/Translations/LanguageKeysTest.php

@@ -98,3 +98,16 @@
     'field.form.description_position_options.below',
     'field.form.description_position_options.above',
 ]);
+
+it('has no duplicate top-level keys in any language file (PHP silently drops earlier definitions)', function (string $path): void {
+    $contents = file_get_contents($path);
+    preg_match_all("/^    '([^']+)' =>/m", $contents, $matches);
+
+    $duplicates = array_filter(array_count_values($matches[1]), fn (int $count): bool => $count > 1);
+
+    expect($duplicates)->toBe([], sprintf(
+        'Duplicate top-level key(s) in %s: %s. PHP keeps only the last definition, masking earlier values.',
+        basename(dirname($path)).'/'.basename($path),
+        implode(', ', array_keys($duplicates)),
+    ));
+})->with(fn () => glob(__DIR__.'/../../../resources/lang/*/*.php'));