fix(adapters): support macOS hosts in port-listening probe and prevent edge container termination

[chbndrhnns]

Closes #646

Summary

On macOS / Darwin hosts (such as local self-hosted Openship servers or developer machines), the edge controller container (openship-edge) was repeatedly terminated with SIGKILL (docker rm -f) during deploys, routing retries, and reconcile passes.

The root cause was in packages/adapters/src/system/port-listen.ts:

• The port probe command used cat /proc/net/tcp 2>/dev/null; cat /proc/net/tcp6 2>/dev/null; true.
• On macOS hosts, /proc does not exist. The command exited 0 with an empty string "".
• parseListeningPorts("") returned an empty set, causing probePortListeningOnce to return false (instead of null for inconclusive).
• waitForPortListening interpreted this as a conclusive negative ({ listening: false, checked: true }).
• ensureContainerEdge's post-start verification (verifyEdgeServing) concluded port 80 failed to bind and executed docker rm -f openship-edge in its catch block.

Changes

• packages/adapters/src/system/port-listen.ts:
  • Replaced the hardcoded procfs command with a tiered buildPortProbeCommand(port):
    1. /proc/net/tcp{,6} on Linux / runtime containers.
    2. lsof -ti tcp:PORT -sTCP:LISTEN / lsof -ti :PORT -sTCP:LISTEN on macOS / Darwin / BSD hosts.
    3. ss -tln sport = :PORT fallback on Linux when procfs is unmounted.
    4. Explicit __UNAVAILABLE__ sentinel when no probe mechanism exists on the target.
  • Added parsePortProbeOutput(out, port):
    • Evaluates procfs headers / rows.
    • Evaluates lsof PIDs and __LISTEN__ / __FREE__ sentinels.
    • Returns null (inconclusive / checked: false) for __UNAVAILABLE__, empty output, or command errors, preventing false-negative container deletions on unmeasurable hosts.
  • Kept PROC_NET_TCP_CMD export for backwards compatibility with tests and callers.
• packages/adapters/src/system/port-listen.test.ts:
  • Added unit tests for buildPortProbeCommand.
  • Added unit tests for parsePortProbeOutput across procfs, lsof single/multi PIDs, __FREE__, __LISTEN__, __UNAVAILABLE__, and empty output.
  • Added test cases in waitForPortListening and waitForPortFree for macOS lsof PIDs, __FREE__, and inconclusive probe handling.

Verification

• Unit tests for port-listen.ts verified across all cases (procfs, macOS lsof, ss sentinels, inconclusive output).
• Verified against live host executor on macOS:
  • Port 80 free: { listening: false, checked: true }
  • Port 80 with running docker container: { listening: true, checked: true }
  • Post-shutdown free verification (waitForPortFree): { free: true, checked: true }