add basic navigation

src/messageTab.tsx

@@ -3,5 +3,9 @@ import * as React from "bloatless-react";
 import { getText } from "./translations";
 
 export function MessageTab() {
-  return <article></article>;
+  return (
+    <article id="message-tab">
+      <header>{getText("messages")}</header>
+    </article>
+  );
 }

src/settingsTab.tsx

@@ -3,5 +3,9 @@ import * as React from "bloatless-react";
 import { getText } from "./translations";
 
 export function SettingsTab() {
-  return <article></article>;
+  return (
+    <article id="settings-tab">
+      <header>{getText("settings")}</header>
+    </article>
+  );
 }