add basic model and interface

src/Views/messageComposer.tsx

@@ -0,0 +1,26 @@
+import * as React from "bloatless-react";
+
+import { cannotSendMessage, messageBody, sendMessage } from "../model";
+
+import { translation } from "../translations";
+
+export function MessageComposer() {
+  return (
+    <div class="flex-row width-100">
+      <input
+        class="width-100 flex-1"
+        style="max-width: unset"
+        placeholder={translation.composerPlaceholder}
+        bind:value={messageBody}
+        on:enter={sendMessage}
+      ></input>
+      <button
+        class="primary"
+        on:click={sendMessage}
+        toggle:disabled={cannotSendMessage}
+      >
+        <span class="icon">send</span>
+      </button>
+    </div>
+  );
+}