Detect provider context exhaustion from Claude Code's structured
terminal_reason rather than from its error prose, so a saturated session is
retired and the next task cold-starts instead of resuming a conversation
that can no longer answer.
Refs #6402 — does not close it: the captured 2.1.220/2.1.221 frames report
is_error alongside terminal_reason, so the specific `completed` escape the
issue reports is not reproduced. The structured check is the load-bearing
fix and is proven present on the reported CLI version; the composite text
predicate is a bounded backstop for uncaptured shapes.
c1bd4f995c