## Why
A retryable failure during the initial remote exec-server connection left the
environment disconnected on subsequent readiness checks.
## What changed
Route retryable startup errors through the existing reconnect path. This lets
later `get()` and `wait_until_ready()` calls establish a replacement client,
while concurrent callers share the same reconnect attempt.
## Testing
Add a WebSocket test that fails the initial handshake, then verifies that later
readiness and client requests share a successful replacement connection.
GitOrigin-RevId: 82d425af0a73331884439b4350a7a1052d4ae865