ops: .dockerignore, non-root user, network isolation, deploy rollback

- .dockerignore excludes .git, node_modules, certs, *.zip
- Dockerfile runs as non-root appuser
- compose.yml isolates frontend (Caddy only) and backend (DB/cache/media) networks
- deploy.sh snapshots binary before pull and rolls back on failed health check

deploy.sh

@@ -8,8 +8,31 @@ export NVM_DIR="$HOME/.nvm"
 [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
 nvm use 22
 
+# Snapshot the current binary before pulling
+if [ -f dumpster-server ]; then
+  cp dumpster-server dumpster-server.bak
+  echo "Backed up existing binary to dumpster-server.bak"
+fi
+
 git pull
 make build
-systemctl restart dumpster
 
-echo "Deploy complete — $(date)"
+# Health check after restart — roll back on failure
+systemctl restart dumpster
+echo "Waiting for app to become healthy..."
+for i in $(seq 1 15); do
+  if curl -sf http://localhost:8080/ > /dev/null 2>&1; then
+    echo "Server is listening — deploy complete"
+    rm -f dumpster-server.bak
+    echo "Deploy complete — $(date)"
+    exit 0
+  fi
+  sleep 2
+done
+
+echo "Health check failed after 30s — rolling back..."
+systemctl stop dumpster
+cp dumpster-server.bak dumpster-server
+systemctl start dumpster
+echo "Rolled back to previous binary — $(date)"
+exit 1