Terminal: Das prompt, dprompt and dbanner (0.9.1)

- das-shell 0.1.0: the Das two-line bash prompt by default (replaces the
  PS1 of Void's skel .bashrc once), dprompt (Textual prompt builder with
  presets and live preview) and dbanner (SSH login banner editor: canvas
  tools, fields with values, widgets, das-banner service for cached ones,
  Das OS logo and tryzub pictures). Python tests in make test.
- das-server 0.3.0 depends on das-shell; the server installer mentions
  dprompt and dbanner; the desktop image includes it.
- run-qemu.sh forwards the guest's SSH to localhost:2222.
- Hardware fixes: Ventoy menu icon, boot menu titles "Das OS <version>".

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

srcpkgs/das-shell/files/bashrc.d/das-prompt.sh

@@ -0,0 +1,14 @@
+# Das OS bash prompt: ~/.config/das/prompt.sh, else /etc/das/prompt.sh (both
+# written by dprompt), else the stock one.
+# shellcheck shell=bash
+
+if [[ $- == *i* && -r /usr/lib/das/prompt-lib.sh ]]; then
+	. /usr/lib/das/prompt-lib.sh
+	for __das_f in "${XDG_CONFIG_HOME:-$HOME/.config}/das/prompt.sh" /etc/das/prompt.sh /usr/share/das/prompt/default.sh; do
+		if [[ -r $__das_f ]]; then
+			. "$__das_f"
+			break
+		fi
+	done
+	unset __das_f
+fi