feat(hub): raise agent turns/time limits and notify teachers on failure

Defaults and silo env go to 150 turns / 1800s wall clock. Run completion
appends a clear Feishu notice for max-turns, timeout, and other failures
(partial answer kept). Startup process-restart kills notify the bound chat.
Release v0.0.38.

hub/src/feishu/card/streaming-card.ts

@@ -129,11 +129,16 @@ export class StreamingAgentCard {
 
   async finish(
     fallbackText: string,
-    options: { readonly interrupted?: boolean; readonly footerText?: string | undefined } = {},
+    options: {
+      readonly interrupted?: boolean;
+      readonly footerText?: string | undefined;
+      readonly isError?: boolean;
+    } = {},
   ): Promise<void> {
     await this.flushChain;
     this.interrupted = options.interrupted === true;
     const footerText = options.footerText ?? "";
+    const isError = options.isError === true;
     const fallbackWithFooter = appendFooter(fallbackText, footerText);
     try {
       let answerText =
@@ -155,11 +160,10 @@ export class StreamingAgentCard {
 
       let updated = true;
       if (answerText.length > 0 || segments.length > 0) {
-        updated = await this.flushCard("complete", answerText, false, segments);
+        updated = await this.flushCard("complete", answerText, isError, segments);
       } else if (this.currentMessageId !== null) {
-        updated = await this.flushCard("complete", "", false, []);
+        updated = await this.flushCard("complete", "", isError, []);
       }
-
       if (!updated) {
         // Card path failed (e.g. residual content policy). Deliver text + standalone images.
         updated = await this.deliverPlainFallback(segments, answerText);