flaky test: shell-run-manager secret redaction across a soft wrap

redacts a secret across a soft wrap and the scrollback/screen boundary in packages/runtime/src/__tests__/shell-run-manager.test.ts fails intermittently on CI.

Observed: run 31716295489, test_workspaces. The case failed at 27.6ms; the enclosing ShellRunProcessManager suite took 8.1s. It surfaced on #2962, which touches only packages/runtime-host/src/client and packages/eval and does not change packages/runtime at all. main was green at the time. Running the case alone locally passes in 549ms.

Suspected cause: the assertion depends on when the PTY flushes across the soft-wrap and scrollback/screen boundary, which shifts under CI load. The fix is to wait for a settled terminal state rather than a particular flush ordering.

This is not a redaction defect — the production behaviour under test looks correct; only the test's timing assumption is unsound.