Trim backup history output to fit Telegram

handlers/backup.py

@@ -436,8 +436,16 @@ async def backup_history(msg: Message):
     if content.startswith("⚠️"):
         await msg.answer(content, reply_markup=backup_kb)
         return
+    trimmed = False
+    max_len = 3500
+    if len(content) > max_len:
+        content = content[-max_len:]
+        trimmed = True
+    header = "📜 Backup history (tail)"
+    if trimmed:
+        header += " (trimmed)"
     await msg.answer(
-        f"📜 Backup history (tail)\n`{log_path}`\n```\n{content}\n```",
+        f"{header}\n`{log_path}`\n```\n{content}\n```",
         reply_markup=backup_kb,
         parse_mode="Markdown",
     )