feat: add emergency fix script for Express version issue

- Add fix-express-version.sh script to manually resolve path-to-regexp errors
- Script performs complete node_modules cleanup and reinstall
- Verifies correct Express 4.19.2 version is installed
- Provides immediate solution while installer is being debugged

Run this script on affected servers:
sudo /opt/pulse/scripts/fix-express-version.sh

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

scripts/fix-express-version.sh

@@ -0,0 +1,99 @@
+#!/bin/bash
+
+# Emergency fix script for Express version issue
+# This script forces a clean reinstall of dependencies with the correct Express version
+
+set -e
+
+print() {
+    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1"
+}
+
+print "Emergency Express version fix for Pulse"
+print "======================================"
+
+# Check if running as root
+if [ "$EUID" -ne 0 ]; then 
+    print "ERROR: This script must be run as root (use sudo)"
+    exit 1
+fi
+
+# Stop the service
+print "Stopping pulse-monitor service..."
+systemctl stop pulse-monitor.service 2>/dev/null || true
+
+# Navigate to Pulse directory
+cd /opt/pulse || {
+    print "ERROR: Could not find /opt/pulse directory"
+    exit 1
+}
+
+# Backup current package.json if needed
+if [ -f package.json ]; then
+    cp package.json package.json.backup
+    print "Backed up package.json"
+fi
+
+# Remove node_modules completely
+print "Removing old node_modules directory..."
+rm -rf node_modules
+
+# Clear npm cache
+print "Clearing npm cache..."
+npm cache clean --force
+
+# Ensure package.json has correct Express version
+print "Checking Express version in package.json..."
+if grep -q '"express": "\^4\.21' package.json; then
+    print "Fixing Express version in package.json..."
+    sed -i 's/"express": "\^4\.21\.[0-9]*"/"express": "4.19.2"/' package.json
+fi
+
+# Show current Express version in package.json
+current_version=$(grep '"express":' package.json | sed 's/.*"express": "\([^"]*\)".*/\1/')
+print "Express version in package.json: $current_version"
+
+# Install dependencies using npm ci
+print "Installing dependencies with npm ci..."
+if npm ci --omit=dev; then
+    print "SUCCESS: Dependencies installed with npm ci"
+else
+    print "WARNING: npm ci failed, trying npm install..."
+    npm install --omit=dev || {
+        print "ERROR: Failed to install dependencies"
+        exit 1
+    }
+fi
+
+# Verify Express version
+installed_version=$(npm list express --depth=0 2>/dev/null | grep express@ | sed 's/.*express@//')
+print "Express version installed: $installed_version"
+
+if [[ "$installed_version" == "4.19.2" ]]; then
+    print "SUCCESS: Correct Express version installed"
+else
+    print "WARNING: Express version mismatch. Expected 4.19.2, got $installed_version"
+fi
+
+# Set correct ownership
+print "Setting correct ownership..."
+chown -R pulse:pulse /opt/pulse
+
+# Start the service
+print "Starting pulse-monitor service..."
+systemctl start pulse-monitor.service
+
+# Wait a moment
+sleep 3
+
+# Check service status
+if systemctl is-active --quiet pulse-monitor.service; then
+    print "SUCCESS: pulse-monitor service is running!"
+    systemctl status pulse-monitor.service --no-pager
+else
+    print "ERROR: Service failed to start. Checking logs..."
+    journalctl -u pulse-monitor.service -n 20 --no-pager
+fi
+
+print "======================================"
+print "Fix script completed"