fix(multi-display): fix runtime directory race condition and SPICE display enabling

- Fix tmpfs race condition in daemon by mounting runtime directory explicitly
  before starting Sway, preventing sockets from being hidden when systemd-logind
  mounts over them later
- Fix enable-displays.py to use correct SpiceClientGLib API methods
  (update_display_enabled/update_display instead of set_display_enabled/set_display)
- Fix virt-viewer monitor-mapping to use 1-indexed client monitors
- Add virt-viewer config setup and automatic display enabling to test script
- Multi-display now works correctly with 3 QXL devices

isotest/run-test.sh

@@ -116,6 +116,14 @@ if ! command -v remote-viewer &> /dev/null; then
     exit 0
 fi
 
+# Set up virt-viewer settings for multi-display
+VIRT_VIEWER_CONFIG_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/virt-viewer"
+mkdir -p "$VIRT_VIEWER_CONFIG_DIR"
+if [ -f "$SCRIPT_DIR/virt-viewer-settings" ]; then
+    cp "$SCRIPT_DIR/virt-viewer-settings" "$VIRT_VIEWER_CONFIG_DIR/settings"
+    echo "Configured virt-viewer for 3 displays"
+fi
+
 # Detect DISPLAY if not set
 if [ -z "$DISPLAY" ]; then
     # Try to find an active X display
@@ -175,18 +183,30 @@ if [ -z "$DISPLAY" ] && [ -z "$WAYLAND_DISPLAY" ]; then
     VIEWER_PID=$!
     echo "remote-viewer running headlessly (PID: $VIEWER_PID)"
 else
-    echo "Launching remote-viewer (DISPLAY=$DISPLAY, WAYLAND_DISPLAY=$WAYLAND_DISPLAY)..."
-    remote-viewer spice://localhost:5930 &
+    echo "Launching remote-viewer with fullscreen for multi-display (DISPLAY=$DISPLAY, WAYLAND_DISPLAY=$WAYLAND_DISPLAY)..."
+    remote-viewer --full-screen spice://localhost:5930 &
     VIEWER_PID=$!
 fi
 echo ""
 
 echo "=== Press Ctrl-C to stop ==="
 echo ""
+
+# Wait for eco-vdagent to be ready in the guest, then enable all 3 displays
+echo "Waiting for eco-vdagent to be ready (10s)..."
+sleep 10
+
+# Enable all 3 displays via SPICE protocol
+if [ -f "$SCRIPT_DIR/enable-displays.py" ]; then
+    echo "Enabling all 3 displays via SPICE protocol..."
+    python3 "$SCRIPT_DIR/enable-displays.py" "spice://localhost:5930" 3 2>&1 || true
+    echo ""
+fi
+
 echo "Tips:"
-echo "  - View > Displays > Enable Display 2/3 for multi-monitor"
 echo "  - pnpm run test:screenshot  - Take screenshot"
 echo "  - http://localhost:3006     - Management UI"
+echo "  - socat - UNIX-CONNECT:.nogit/vm/serial.sock  - Serial console (login: ecouser/ecouser)"
 echo ""
 
 # Wait for either process to exit