chore: import upstream snapshot with attribution

apps/sim/lib/table/rows/paging.ts

@@ -0,0 +1,23 @@
+/**
+ * Cuts a fetched page to a byte budget: keeps the longest prefix of rows whose
+ * serialized `data` fits within `maxBytes`, always keeping at least one row so
+ * pagination makes forward progress even when a single row exceeds the budget.
+ *
+ * The budget counts `data` only — the per-row envelope (`id`, `position`,
+ * `orderKey`, timestamps, executions) is not measured, so actual response
+ * payloads run slightly over `maxBytes`. Callers must leave headroom; the
+ * production SQL-side cut should account for the same overhead.
+ */
+export function trimRowsToByteBudget<T extends { data: unknown }>(
+  rows: T[],
+  maxBytes: number
+): T[] {
+  let total = 0
+  let kept = 0
+  for (const row of rows) {
+    total += Buffer.byteLength(JSON.stringify(row.data))
+    if (kept > 0 && total > maxBytes) break
+    kept++
+  }
+  return kept === rows.length ? rows : rows.slice(0, kept)
+}