## What changed
- Replace pending WebSocket URL registration with deferred Noise environment
registration that gates connection attempts on an explicit readiness signal.
- Reuse the Noise rendezvous transport after readiness so reconnects request a
fresh connection bundle.
- Preserve terminal errors for failed or dropped registrations and keep late
completion isolated from replacement environments.
## Testing
- Add coverage for readiness gating, registration failure and replacement,
eager Noise connections, and reconnection through a fresh rendezvous bundle.
GitOrigin-RevId: 83e23fa03a02e3b2bdf1a83fe26d7ac461f55cf3