PR: Vault Service Robustness & Monitoring

Summary

Improves the vault federated client reliability for unattended operation on third-party servers, and adds admin visibility into vault health.

Changes

Vault Client

• Strict env var validation at startup (fail fast on missing config)
• WebSocket reconnection with exponential backoff and infinite retries
• Graceful shutdown handling (SIGTERM/SIGINT, double-signal to force quit)
• Heartbeat reporting to central API every 30s with status and running computations

Central API

• New vaultHeartbeat mutation for vault status updates
• VaultStatus field on vault users (status, version, uptime, running computations)
• getVaultUserList now returns real-time vault health data

Admin UI

• Vault status table on admin page showing online/offline status, last seen, running computations
• Auto-refresh every 30s

Deployment

• Added Dockerfile-vault for containerized deployment
• Added docker-compose.vault.yaml example with restart policy
• Added neuroflame-vault.service systemd unit file

Fixed

• Typo: VAULT_BASE_IDR → VAULT_BASE_DIR
• TypeScript compilation issues in vault client