Netis Cloud Probe Files

## ⚠️ Breaking Changes

• cpctl CLI restructured. The worker subcommand layer has been removed; ping, info, and stats are now top-level commands (e.g. cpctl worker stats → cpctl stats).
• Flag renamed. --control / -s is now --unix / -u and takes a raw unix socket path. Update any scripts or automation that invoke cpctl.

## ✨ Features

• ZMQ heartbeat packets. When no real traffic is flowing, cpworker now emits lightweight MPLS-encapsulated heartbeat packets so the ZMQ receiver (RecvZMQ) can keep advancing its merge watermark. Configurable via zmq.heartbeat_ms (default 1000, set to 0 to disable).
• cpctl improvements. New ping and info control commands, and a new --timeout flag plumbed through RPC context deadlines.

## 🐛 Bug Fixes

• GRE / VXLAN pmtudisc=0 now honored. Previously only values > 0 were applied, making it impossible to explicitly disable PMTU discovery (IP_PMTUDISC_DONT). A value of 0 is now passed through to setsockopt.
• BPF filter now excludes output hosts across all tasks. When multiple tasks share a capture interface, each task's filter must exclude every output host from all tasks to avoid capturing forwarded traffic. Output hosts are now deduplicated so each appears only once.

## 🔒 Hardening

• Build scripts no longer leak the SSH root password. run_ssh_root pipes the password through ssh stdin instead of interpolating it into the remote command string, so it no longer appears in ps on either end (also fixes breakage when the password contained a single quote).
• unix-manager slow-reader protection. Client connections now use a 5s send timeout (SO_SNDTIMEO). A client that opens the socket and stops draining can no longer stall the single-threaded select loop serving other clients; the send returns EAGAIN and the stuck client is torn down.

## 🛠 Internal / Tooling

• Added a justfile and scripts/routers/* to unify local / SSH / OrbStack build dispatch.
• Expanded integration and Go / C / shell unit tests (including a zmq_heartbeat case); added the CPW_SKIP_ENV_LOCAL escape hatch.

### Upgrade note

zmq.heartbeat_ms defaults to 1000ms, so ZMQ outputs will start emitting heartbeat packets after upgrading. Set zmq.heartbeat_ms: 0 to preserve the previous (no-heartbeat) behavior.

Full Changelog: https://github.com/Netis/cloud-probe/compare/v0.9.1...v0.9.2