fix: script portability and npm security updates

Scripts:
- stop.sh: replace Linux-only fuser with cross-platform lsof fallback
- start.sh: parameterize port (APP_PORT) and container name (dynamic lookup)
- app-dev-start.sh: cross-platform stat (GNU -c / BSD -f) and setpriv/su fallback
- deploy-compose.sh: parameterize Docker registry via DOCKER_REGISTRY env var
- harden-postgres.sh: make DB_USER and DB_NAME configurable via env vars

NPM security:
- next: 15.5.12 → 15.5.15 (fixes HTTP request smuggling CVE)
- nodemailer: 8.0.1 → 8.0.5 (fixes SMTP command injection CVEs)
- lodash-es: add pnpm override to force >=4.18.0 (fixes code injection + prototype pollution)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/harden-postgres.sh

@@ -2,8 +2,8 @@
 # Remove SUPERUSER from the application database user
 # Run after initial setup: bash scripts/harden-postgres.sh
 
-DB_USER="capakraken"
-DB_NAME="capakraken"
+DB_USER="${DB_USER:-capakraken}"
+DB_NAME="${DB_NAME:-capakraken}"
 
 echo "Hardening PostgreSQL for $DB_USER..."