📝(documentation) adds customization for translations

Part of customization PoC

Signed-off-by: Robin Weber <weber@b1-systems.de>

CHANGELOG.md

@@ -8,6 +8,10 @@ and this project adheres to
 
 ## [Unreleased]
 
+### Added
+
+- ✨(frontend) add customization for translations #857
+
 ## [3.3.0] - 2025-05-06
 
 ### Added

docs/theming.md

@@ -53,4 +53,18 @@ Below is a visual example of a configured footer ⬇️:
 
 ![Footer Configuration Example](./assets/footer-configurable.png)
 
+----
 
+# **Custom Translations** 📝
+
+The translations can be partially overridden from the theme customization file.
+
+### Settings 🔧
+
+```shellscript
+THEME_CUSTOMIZATION_FILE_PATH=<path>
+```
+
+### Example of JSON
+
+The json must follow some rules: https://github.com/suitenumerique/docs/blob/main/src/helm/env.d/dev/configuration/theme/demo.json

src/helm/env.d/dev/configuration/theme/demo.json

@@ -1,4 +1,12 @@
 {
+  "translations": {
+    "en": {
+      "translation": {
+        "Docs": "MyDocs",
+        "New doc": "+"
+      }
+    }
+  },
   "footer": {
     "default": {
       "logo": {