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>

Makefile

@@ -10,7 +10,7 @@ help:
 	@echo "make qemu-bios  boot the newest ISO in QEMU with legacy BIOS"
 	@echo "make qemu-disk  boot with a 20 GB virtual disk attached (for installer tests)"
 	@echo "make qemu-server boot the newest server ISO on a serial console, with the disk"
-	@echo "make test       run Go tests"
+	@echo "make test       run Go and Python tests"
 	@echo "make clean      remove build output (keeps download caches)"
 
 packages:
@@ -37,6 +37,7 @@ qemu-server:
 test:
 	cd srcpkgs/das-theme/files/xfwm4gen && go test ./...
 	cd srcpkgs/das-tools/files/src && go test ./...
+	cd srcpkgs/das-shell/files && PYTHONDONTWRITEBYTECODE=1 python3 -m unittest discover -s tests -t .
 
 # Build output may be owned by root when a build was interrupted, so remove it from the container
 clean: