speed up admin ui polling and payloads

gateway.mjs

@@ -1117,7 +1117,8 @@ function buildLogsSnapshot(monitor, sinceSeq = null) {
   };
 }
 
-async function buildPersistentLogsSnapshot(runtime, sinceSeq = null) {
+async function buildPersistentLogsSnapshot(runtime, sinceSeq = null, limit = 500) {
+  const safeLimit = Number.isInteger(limit) && limit > 0 ? Math.min(limit, 1000) : 500;
   const text = runtime.logPath ? await readOptionalText(runtime.logPath) : null;
   if (!text) {
     return buildLogsSnapshot(runtime.monitor, sinceSeq);
@@ -1129,7 +1130,7 @@ async function buildPersistentLogsSnapshot(runtime, sinceSeq = null) {
     .map((line, index) => parseLogLine(line, index + 1));
   const entries = Number.isInteger(sinceSeq)
     ? allEntries.filter((entry) => entry.seq > sinceSeq)
-    : allEntries.slice(-500);
+    : allEntries.slice(-safeLimit);
 
   return {
     total_entries: allEntries.length,
@@ -1945,10 +1946,16 @@ async function handleManagementRequest(runtime, req, res, requestUrl) {
 
   if (pathname === LOGS_API_PATH && req.method === "GET") {
     const sinceSeqRaw = requestUrl.searchParams.get("since_seq");
+    const limitRaw = requestUrl.searchParams.get("limit");
     const sinceSeq = sinceSeqRaw === null ? null : Number.parseInt(sinceSeqRaw, 10);
+    const limit = limitRaw === null ? 500 : Number.parseInt(limitRaw, 10);
     jsonResponse(res, 200, {
       ok: true,
-      ...await buildPersistentLogsSnapshot(runtime, Number.isInteger(sinceSeq) ? sinceSeq : null),
+      ...await buildPersistentLogsSnapshot(
+        runtime,
+        Number.isInteger(sinceSeq) ? sinceSeq : null,
+        Number.isInteger(limit) ? limit : 500,
+      ),
     });
     return true;
   }