perf(custody-probes): order by partition key for ClickHouse early cutoff

Order int_custody_probe_order_by_slot queries by slot_start_date_time
(partition key) instead of probe_date_time. This allows ClickHouse to use
early cutoff optimization and avoid scanning 27M+ rows just to fetch 30-50
results. Since slot_start_date_time and probe_date_time are nearly identical,
the result ordering is unchanged.

Author: samcm

src/pages/ethereum/data-availability/custody/components/CellProbeDialog/CellProbeDialog.tsx

@@ -178,7 +178,8 @@ export function CellProbeDialog({
       // Filter by column - uses column_indices_has (array contains)
       column_indices_has: cellContext.columnIndex,
       page_size: MAX_PROBES,
-      order_by: 'probe_date_time desc',
+      // Order by slot_start_date_time (partition key) for efficient ClickHouse early cutoff
+      order_by: 'slot_start_date_time desc',
       // Filter out pre-Fulu slots server-side (PeerDAS only exists after Fulu)
       slot_gte: fuluActivation.slot,
     };

src/pages/ethereum/data-availability/custody/components/LiveProbeEvents/LiveProbeEvents.tsx

@@ -111,7 +111,8 @@ export function LiveProbeEvents({
       query: {
         ...queryParams,
         page_size: maxEvents,
-        order_by: 'probe_date_time desc',
+        // Order by slot_start_date_time (partition key) for efficient ClickHouse early cutoff
+        order_by: 'slot_start_date_time desc',
         // Filter out pre-Fulu slots server-side (PeerDAS only exists after Fulu)
         ...(fuluActivation && { slot_gte: fuluActivation.slot }),
       },