feat: add intlayer JSON schema and supporting test cases (#5749)

Author: aymericzip

src/api/json/catalog.json

@@ -3947,6 +3947,17 @@
       "fileMatch": ["main_structure.yml"],
       "url": "https://raw.githubusercontent.com/instant-python/instant-python/main/schemas/main-structure-schema.json"
     },
+    {
+      "name": "intlayer",
+      "description": "Intlayer dictionary content declaration file",
+      "fileMatch": [
+        "*.content.json",
+        "*.content.yaml",
+        "*.content.yml",
+        "*.content.toml"
+      ],
+      "url": "https://www.schemastore.org/intlayer.json"
+    },
     {
       "name": "ioBroker Configuration",
       "description": "The configuration file of an ioBroker installation",

src/negative_test/intlayer/additional_property.json

@@ -0,0 +1,8 @@
+{
+  "$schema": "../../schemas/json/intlayer.json",
+  "content": {
+    "simpleString": "Hello world"
+  },
+  "key": "app-settings",
+  "someAdditionalProp": "should fail"
+}

src/negative_test/intlayer/invalid_plural.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "../../schemas/json/intlayer.json",
+  "content": {
+    "pluralNode": {
+      "nodeType": "plural",
+      "plural": {
+        "one": "One element"
+      }
+    }
+  },
+  "key": "app-settings"
+}

src/negative_test/intlayer/missing_key.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "../../schemas/json/intlayer.json",
+  "content": {
+    "simpleString": "Hello world"
+  }
+}