feat(dev_tools): add translation editor for browsing and editing UI translations

New admin page to browse, search, compare, and inline-edit translation
keys across all modules and languages from the browser.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/dev_tools/locales/en.json

@@ -14,7 +14,24 @@
         "components": "Components",
         "icons": "Icons",
         "sql_query": "SQL Query",
-        "platform_debug": "Platform Debug"
+        "platform_debug": "Platform Debug",
+        "translation_editor": "Translation Editor"
+    },
+    "translation_editor": {
+        "title": "Translation Editor",
+        "all_modules": "All Modules",
+        "search_placeholder": "Search keys and values...",
+        "filter_all": "All",
+        "filter_missing": "Missing",
+        "filter_variables": "Variables",
+        "module": "Module",
+        "key_path": "Key Path",
+        "missing": "missing",
+        "saving": "Saving...",
+        "no_results": "No translation keys match your filters.",
+        "loading": "Loading translations...",
+        "previous": "Previous",
+        "next": "Next"
     },
     "sql_query": {
         "title": "SQL Query Tool",