Gateway: keep whole T3 history pages, and show a command's first line as its activity

gateway/src/views.ts

@@ -93,7 +93,10 @@ function windowCursor(start: number, bounded: BoundedThread): string | null {
   return bounded.hasMoreHistory && bounded.historyCursor ? `h${bounded.historyCursor}` : null;
 }
 
-/** Up to 20 messages before `cursor`. T3 pages without messages are skipped, three at most. */
+/**
+ * The messages before `cursor`: 20 from the bounded window, or one T3 page, which can hold more.
+ * T3 pages without messages are skipped, three at most.
+ */
 export async function loadHistory(host: T3Host, thread: ThreadShell, cursor: string): Promise<HistoryResponse> {
   if (cursor.startsWith("w")) {
     const end = Number(cursor.slice(1));
@@ -120,7 +123,7 @@ export async function loadHistory(host: T3Host, thread: ThreadShell, cursor: str
           createdAt: item.startedAt ?? item.updatedAt ?? "",
         }),
       );
-    if (messages.length > 0) return { messages: messages.slice(-MESSAGES_PER_THREAD), earlierCursor: next && `h${next}` };
+    if (messages.length > 0) return { messages, earlierCursor: next && `h${next}` };
   }
   return { messages: [], earlierCursor: next && `h${next}` };
 }
@@ -139,7 +142,9 @@ export function currentActivity(turnItems: TurnItem[]): Activity | null {
 function describeStep(item: TurnItem): Omit<Activity, "startedAt"> | null {
   switch (item.type) {
     case "command_execution":
-      return item.monitor || typeof item.input !== "string" ? null : { kind: "command", text: item.input };
+      return item.monitor || typeof item.input !== "string"
+        ? null
+        : { kind: "command", text: item.input.split("\n").find((line) => line.trim()) ?? item.input };
     case "file_change":
       return item.fileName ? { kind: "edit", text: item.fileName.split("/").pop()! } : null;
     case "file_search":