Code-based authorization for Drop clients (#145)

* feat: code-based authorization

* fix: final touches

* fix: require session on code fetch endpoint

* feat: better error handling

* refactor: move auth send to client handler

* fix: lint

components/UserHeader/UserWidget.vue

@@ -100,6 +100,11 @@ const navigation = computed<NavigationItem[]>(() =>
       route: "/account",
       prefix: "",
     },
+    {
+      label: "Authorize client",
+      route: "/client/code",
+      prefix: "",
+    },
   ].filter((e) => e !== undefined),
 );
 </script>