Add ErrorBurstGuardState interface tracking threshold/windowTurns/errorTurnCount/recentTurnIds/recentErrorSummary/suggestedCooldownSeconds/triggeredAtTurnId, implement error-burst detection with ERROR_BURST_THRESHOLD=3/WINDOW_TURNS=5/COOLDOWN_SECONDS=45 constants, add isErrorLlmLogEntry/describeErrorLlmLogEntry/collectRecentErrorTurns helpers to identify repl_error/repl_result with errorCount/feedback