ercot-brief.sh: LZ_SOUTH RTM now + 24h peak -> GREEN/WATCH/ELEVATED/CRITICAL
risk level + actions (precharge battery, defer class-3 batch, RTW
counterfactual flag) + TSV history. Rationale: Base Power stays the retail
counterparty; ISO signals are risk intelligence, not an export market.
https://projects.knownelement.com/issues/826#note-7
