feat(i18n): add da/en locale pipeline and shared backend key resolver

shared/i18n/lobby.json

@@ -1,14 +1,42 @@
 {
+  "locales": {
+    "default": "en",
+    "supported": ["en", "da"]
+  },
   "frontend": {
     "errors": {
-      "session_code_required": "Session code is required.",
-      "session_fetch_failed": "Could not load lobby status.",
-      "join_failed": "Join failed. Check code or nickname and try again.",
-      "start_round_failed": "Could not start round. Refresh the lobby and try again.",
-      "session_not_found": "Session code is invalid or the session no longer exists.",
-      "nickname_invalid": "Nickname must be between 2 and 40 characters.",
-      "nickname_taken": "Nickname is already taken.",
-      "unknown": "Action failed. Refresh status and try again."
+      "session_code_required": {
+        "en": "Session code is required.",
+        "da": "Sessionskoden er påkrævet."
+      },
+      "session_fetch_failed": {
+        "en": "Could not load lobby status.",
+        "da": "Kunne ikke indlæse lobby-status."
+      },
+      "join_failed": {
+        "en": "Join failed. Check code or nickname and try again.",
+        "da": "Kunne ikke joine. Tjek kode eller kaldenavn og prøv igen."
+      },
+      "start_round_failed": {
+        "en": "Could not start round. Refresh the lobby and try again.",
+        "da": "Kunne ikke starte runden. Opdater lobbyen og prøv igen."
+      },
+      "session_not_found": {
+        "en": "Session code is invalid or the session no longer exists.",
+        "da": "Sessionskoden er ugyldig, eller sessionen findes ikke længere."
+      },
+      "nickname_invalid": {
+        "en": "Nickname must be between 2 and 40 characters.",
+        "da": "Kaldenavn skal være mellem 2 og 40 tegn."
+      },
+      "nickname_taken": {
+        "en": "Nickname is already taken.",
+        "da": "Kaldenavnet er allerede taget."
+      },
+      "unknown": {
+        "en": "Action failed. Refresh status and try again.",
+        "da": "Handlingen fejlede. Opdater status og prøv igen."
+      }
     }
   },
   "backend": {
@@ -22,6 +50,44 @@
       "category_not_found": "category_not_found",
       "round_start_invalid_phase": "round_start_invalid_phase",
       "round_already_configured": "round_already_configured"
+    },
+    "errors": {
+      "session_code_required": {
+        "en": "Session code is required",
+        "da": "Sessionskode er påkrævet"
+      },
+      "nickname_invalid": {
+        "en": "Nickname must be between 2 and 40 characters",
+        "da": "Kaldenavn skal være mellem 2 og 40 tegn"
+      },
+      "session_not_found": {
+        "en": "Session not found",
+        "da": "Session blev ikke fundet"
+      },
+      "session_not_joinable": {
+        "en": "Session is not joinable",
+        "da": "Sessionen kan ikke joine nu"
+      },
+      "nickname_taken": {
+        "en": "Nickname already taken",
+        "da": "Kaldenavnet er allerede taget"
+      },
+      "category_slug_required": {
+        "en": "category_slug is required",
+        "da": "category_slug er påkrævet"
+      },
+      "category_not_found": {
+        "en": "Category not found",
+        "da": "Kategori blev ikke fundet"
+      },
+      "round_start_invalid_phase": {
+        "en": "Round can only be started from lobby",
+        "da": "Runden kan kun startes fra lobbyen"
+      },
+      "round_already_configured": {
+        "en": "Round already configured",
+        "da": "Runden er allerede konfigureret"
+      }
     }
   }
 }