Add network node status endpoint

[zjma]

Summary

• add /status and /debug/status to network-node user and secrets HTTP servers
• return version, public runtime config, and dependency probe results without exposing private keys/API keys
• probe ACE deployment/fullnode RPCs, configured per-chain RPCs, Solana RPCs, and handler->maintainer /secrets reachability
• inject image tag/release/git SHA into Docker images for status reporting

Testing

• cargo test -p network-node
• git diff --cached --check before commit