fix(mocks): fold the audit window, and append MPE_AUDIT under its lock

Two review findings on this branch.

- editors/restore.js spread every audit row for the load into Math.min(...).
  MPE_AUDIT is append-only, so a long-lived estate would eventually exceed the
  engine's argument limit and the RangeError would surface as a failed restore
  of a perfectly restorable load. Folded into a reduce with an Infinity seed.

- auditors/postdata.js appended to MPE_AUDIT as a read-modify-write outside any
  lock. postdata.sas locks the table it writes - MPE_REVIEW around its proc
  append, MPE_SUBMIT around its update - so the audit append now takes the
  MPE_AUDIT lock around a fresh read, the concat and the save, rather than
  reading the table up front and saving a copy that may be missing another
  approval's rows.

53 mock tests pass (node --test sas/mocks/test/).

sas/mocks/sasjs/services/auditors/postdata.js

@@ -728,11 +728,10 @@ if (action === 'SHOW_DIFFS') {
             .join('|')
         )
 
-      const auditTable = mpeLoadTableData('MPE_AUDIT') || {
-        name: 'MPE_AUDIT',
-        columns: [],
-        rows: []
-      }
+      // The rows this approval adds. They are appended to the table under the
+      // MPE_REVIEW lock below, not to a copy read here: two approvals landing
+      // together would otherwise each save a table without the other's rows.
+      const pending = []
 
       const entry = (row, moveType, column, oldVal, newVal, isPk, isDiff) => {
         const type = column.type === 'N' ? 'N' : 'C'
@@ -759,7 +758,7 @@ if (action === 'SHOW_DIFFS') {
         }
         put('OLDVAL', oldVal)
         put('NEWVAL', newVal)
-        auditTable.rows.push(auditRow)
+        pending.push(auditRow)
       }
 
       const isKey = (name) =>
@@ -792,7 +791,23 @@ if (action === 'SHOW_DIFFS') {
         }
       }
 
-      if (auditTable.rows.length) saveTableToLib('MPE_AUDIT', auditTable)
+      if (pending.length) {
+        // postdata.sas locks the table it appends to (MPE_REVIEW around its
+        // proc append, MPE_SUBMIT around its update), so the audit append takes
+        // the MPE_AUDIT lock rather than borrowing the review one.
+        lockControl('MPE_AUDIT', loadRef + ' Approval')
+        try {
+          const fresh = mpeLoadTableData('MPE_AUDIT') || {
+            name: 'MPE_AUDIT',
+            columns: [],
+            rows: []
+          }
+          fresh.rows = (fresh.rows || []).concat(pending)
+          saveTableToLib('MPE_AUDIT', fresh)
+        } finally {
+          unlockControl('MPE_AUDIT')
+        }
+      }
     } catch (err) {
       // an audit failure must not undo an approval that already landed
       console.log('Error writing MPE_AUDIT: ' + err.message)

sas/mocks/sasjs/services/editors/restore.js

@@ -115,8 +115,9 @@ try {
   // The load's timestamp, then every change to that table from then on: the
   // change to revert plus all subsequent ones.
 
-  const stamp = Math.min(
-    ...mine.map((row) => Number(colVal(row, 'PROCESSED_DTTM')))
+  const stamp = mine.reduce(
+    (min, row) => Math.min(min, Number(colVal(row, 'PROCESSED_DTTM'))),
+    Infinity
   )
   const window = all.filter(
     (row) =>