Instructions per chat (system prompt addition; UI dialog and Telegram /prompt)

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: ["Instructions per chat: ⋯ → Instructions for this chat (Telegram: /prompt)"],
+    de: ["Anweisungen pro Chat: ⋯ → Anweisungen für diesen Chat (Telegram: /prompt)"],
+  },
   "202611-00007": {
     en: ["Telegram: connect your own bot under Settings → Account → Telegram and chat with CodeCraft from your phone"],
     de: ["Telegram: eigenen Bot unter Einstellungen → Konto → Telegram verbinden und von unterwegs mit CodeCraft chatten"],