Markdown in user messages, with a preview in the composer

User messages are rendered with the same Markdown component as the model's
answers; single line breaks are kept (hard breaks outside code blocks), so
plain multi-line messages look as before. The eye button next to the text
field shows the formatted message before sending. The text sent to the model
is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/whatsnew.ts

@@ -3,6 +3,10 @@
  * under "unreleased"; scripts/release.sh renames the key to the release version.
  */
 export const WHATS_NEW: Record<string, { en: string[]; de: string[] }> = {
+  unreleased: {
+    en: ["Your messages are shown as Markdown; the eye button next to the text field previews it before sending"],
+    de: ["Deine Nachrichten werden als Markdown dargestellt; das Augen-Symbol neben dem Textfeld zeigt vor dem Senden eine Vorschau"],
+  },
   "202611-00014": {
     en: ["Folder picker (new automation, new chat): create a new folder right there"],
     de: ["Ordnerauswahl (neue Automatisierung, neuer Chat): direkt einen neuen Ordner anlegen"],