feat: desktop computer-use APIs with neko-based streaming

Add desktop runtime management (Xvfb, openbox, dbus), screen capture,
mouse/keyboard input, and video streaming via neko binary extracted
from the m1k1o/neko container. Includes Docker test rig, TypeScript SDK
desktop support, and inspector Desktop tab.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.context/docker-test-zgvGyf/bin/Xvfb

@@ -0,0 +1,15 @@
+#!/usr/bin/env sh
+set -eu
+display="${1:-:191}"
+number="${display#:}"
+socket="/tmp/.X11-unix/X${number}"
+mkdir -p /tmp/.X11-unix
+touch "$socket"
+cleanup() {
+  rm -f "$socket"
+  exit 0
+}
+trap cleanup INT TERM EXIT
+while :; do
+  sleep 1
+done