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/share/banner/art/trident.json

@@ -0,0 +1,46 @@
+{
+  "name": "trident",
+  "title": {
+    "uk": "Тризуб",
+    "en": "Tryzub"
+  },
+  "styles": {
+    "a": {
+      "fg": "bright_yellow",
+      "bg": null,
+      "bold": false
+    }
+  },
+  "lines": [
+    "",
+    "         ██",
+    "   █▄    ██    ▄█",
+    "   █▀█   ██   █▀█",
+    "   █ ██  ██  ██ █",
+    "   █  █  ██  █  █",
+    "   █  █  ██  █  █",
+    "   █▄█  █▀▀█  █▄█",
+    "   █ ▀▄██  ██▄▀ █",
+    "   █   █ ██ █   █",
+    "   ▀▀▀▀█▀██▀█▀▀▀▀",
+    "       ▀████▀",
+    "         ▀▀",
+    ""
+  ],
+  "style_map": [
+    "",
+    "         aa",
+    "   aa    aa    aa",
+    "   aaa   aa   aaa",
+    "   a aa  aa  aa a",
+    "   a  a  aa  a  a",
+    "   a  a  aa  a  a",
+    "   aaa  aaaa  aaa",
+    "   a aaaa  aaaa a",
+    "   a   a aa a   a",
+    "   aaaaaaaaaaaaaa",
+    "       aaaaaa",
+    "         aa",
+    ""
+  ]
+}