Improve clipboard guidance for KDE users

README.md

@@ -50,6 +50,12 @@ Or start the app without env vars and enter them interactively when prompted.
 When entered in the TUI, the app now stores `api_id` and `api_hash` in
 `~/.local/share/telegram-tui/config.json` and reuses them on later launches.
 
+Clipboard image sending via `>paste` or `>clip` requires an external clipboard tool:
+- `wl-clipboard` on Wayland or KDE Plasma Wayland
+- `xclip` on X11
+
+Klipper by itself is not a supported image backend for this feature.
+
 To use Telegram test servers instead of production:
 
 ```bash