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/tests/common.py

@@ -0,0 +1,21 @@
+"""Points das_shell at the source tree and a scratch /etc before it is imported."""
+
+import os
+import sys
+import tempfile
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+FILES = os.path.dirname(HERE)
+SCRATCH = tempfile.mkdtemp(prefix="das-shell-test-")
+
+os.environ.update({
+    "DAS_SHELL_DATA": os.path.join(FILES, "share"),
+    "DAS_SHELL_LIB": FILES,
+    "DAS_SHELL_ETC": os.path.join(SCRATCH, "etc"),
+    "DAS_SHELL_CACHE": os.path.join(SCRATCH, "cache"),
+    "XDG_CONFIG_HOME": os.path.join(SCRATCH, "config"),
+    "LANG": "en_US.UTF-8",
+})
+os.environ.pop("LC_ALL", None)
+os.environ.pop("LC_MESSAGES", None)
+sys.path.insert(0, os.path.join(FILES, "python"))