Restart the QML deadline when generation starts, so preparation no longer
shortens the 185-second window that must outlast the 180-second shell bound.

Accept a prepared input only at the helper's canonical
codexbar-plasma-ai-<uid>/<request>/payload.ini path, rejecting empty and dot
segments that QtCore.Settings would resolve elsewhere. The helper normalizes
its runtime or temporary base so legitimate roots still match.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>