add: setup inlang translation

assets/translations/en.json

@@ -0,0 +1,4 @@
+{
+  "appName": "Hiddify Next",
+  "Error": "Error"
+}

project.inlang.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "https://inlang.com/schema/project-settings",
+  "sourceLanguageTag": "en",
+  "languageTags": [
+    "en",
+    "fa",
+    "ru-RU",
+    "zh-CN"
+  ],
+  "modules": [
+    "https://cdn.jsdelivr.net/npm/@inlang/plugin-i18next@4/dist/index.js",
+    "https://cdn.jsdelivr.net/npm/@inlang/message-lint-rule-empty-pattern@1/dist/index.js",
+    "https://cdn.jsdelivr.net/npm/@inlang/message-lint-rule-identical-pattern@1/dist/index.js",
+    "https://cdn.jsdelivr.net/npm/@inlang/message-lint-rule-without-source@1/dist/index.js",
+    "https://cdn.jsdelivr.net/npm/@inlang/message-lint-rule-missing-translation@1/dist/index.js"
+  ],
+  "plugin.inlang.i18next": {
+    "pathPattern": "./assets/translations/{languageTag}.json",
+    "variableReferencePattern": [
+      "@:"
+    ]
+  }
+}
+