fix: move Chromium download to Docker build phase

- Download Chromium from Google snapshots during Docker build (network works there)
- Chroot hook now only verifies and installs runtime dependencies
- Remove generated files from repo (OVMF_VARS.fd, qemu.pid, screenshots)
- Update isotest scripts to use .nogit/ directory structure
- Chromium kiosk verified working with Sway compositor

isotest/screenshot.sh

@@ -1,14 +1,16 @@
 #!/bin/bash
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
-MONITOR_SOCK="$SCRIPT_DIR/qemu-monitor.sock"
-SCREENSHOT_DIR="$SCRIPT_DIR/screenshots"
+PROJECT_ROOT="$SCRIPT_DIR/.."
+VM_DIR="$PROJECT_ROOT/.nogit/vm"
+SCREENSHOT_DIR="$PROJECT_ROOT/.nogit/screenshots"
+MONITOR_SOCK="$VM_DIR/qemu-monitor.sock"
 TIMESTAMP=$(date +%Y%m%d-%H%M%S)
 
 # Check if QEMU is running
 if [ ! -S "$MONITOR_SOCK" ]; then
     echo "ERROR: QEMU not running (no monitor socket)"
-    echo "Run 'npm run test' first to start the VM"
+    echo "Run 'pnpm run test' first to start the VM"
     exit 1
 fi