fbe086f7cc
Builds on diffen77's #66547 (cherry-picked as the previous commits). Extend _is_session_expired_error's iterative traversal to follow __cause__/__context__ in addition to ExceptionGroup .exceptions — SDK wrappers often raise a generic RuntimeError *from* the message-less ClosedResourceError, leaving the transport signal reachable only via the chain. The identity-visited set guards chain cycles (handlers re-raising previously seen exceptions), and a bounded node budget (_EXC_TRAVERSAL_MAX_NODES) caps pathological acyclic graphs. Adds regression tests: cause/context chain detection, interruption precedence through chains, cyclic cause/context termination, and budget-bounded termination.