Loopback WebSocket integration proof: PR 19426
Base supervisor: 1451e7cb23034d29774338608368a15d8845df36
Rebuilt head: aa7bb7087eb8390248c6fd8ea06329a21bc105ca
Production RpcSession + EnvironmentSupervisor, Node 24 built-in WebSocket client, ws loopback server; synthetic config, no account credentials.
Base comparison substitutes only the base supervisor; both use the current RpcSession. Timers delay server replies; stream/Promise milestones await results, no polling.

{"mode": "main-before", "elapsedMs": 3014, "connections": 2, "outcome": "healthy delayed probe lost at old quick deadline"}
{"mode": "slow", "elapsedMs": 8006, "connections": 1, "rawFrames": 4, "outcome": "same connection survived delayed 8s probe"}
{"mode": "silent", "elapsedMs": 6018, "connections": 2, "outcome": "replaced connection at bounded deadline"}
{"mode": "cap", "elapsedMs": 15022, "connections": 2, "outcome": "replaced connection at bounded deadline"}

Not a deployed relay, real slow WAN, browser, mobile, or Electron proof. Native device access is disabled. All owned loopback servers closed.