fix: add fetch timeout and wide event logging to ComputeWorkloadManager

The fetch() call had no timeout, causing infinite hangs when the gateway
accepted requests but never returned responses. Adds AbortSignal.timeout
(30s) and consolidates all logging into a single structured event per
create() call with timing, status, and error context.

apps/supervisor/src/workloadManager/compute.ts

@@ -25,8 +25,6 @@ export class ComputeWorkloadManager implements WorkloadManager {
   }
 
   async create(opts: WorkloadManagerCreateOptions) {
-    this.logger.log("create()", { opts });
-
     const runnerId = getRunnerId(opts.runFriendlyId, opts.nextAttemptNumber);
 
     const envVars: Record<string, string> = {
@@ -81,10 +79,20 @@ export class ComputeWorkloadManager implements WorkloadManager {
 
     const url = `${this.opts.gatewayUrl}/api/sandboxes`;
 
+    const event: Record<string, unknown> = {
+      runId: opts.runFriendlyId,
+      runnerId,
+      image: imageRef,
+      url,
+    };
+
+    const startMs = performance.now();
+
     const [fetchError, response] = await tryCatch(
       fetch(url, {
         method: "POST",
         headers,
+        signal: AbortSignal.timeout(30_000),
         body: JSON.stringify({
           image: imageRef,
           env: envVars,
@@ -92,28 +100,41 @@ export class ComputeWorkloadManager implements WorkloadManager {
       })
     );
 
+    event.durationMs = Math.round(performance.now() - startMs);
+
     if (fetchError) {
-      this.logger.error("Failed to create sandbox", { error: fetchError, url });
+      event.ok = false;
+      event.error = fetchError instanceof Error ? fetchError.message : String(fetchError);
+      event.errorType =
+        fetchError instanceof DOMException && fetchError.name === "TimeoutError"
+          ? "timeout"
+          : "fetch";
+      this.logger.error("create sandbox", event);
       return;
     }
 
+    event.status = response.status;
+
     if (!response.ok) {
       const [bodyError, body] = await tryCatch(response.text());
-      this.logger.error("Gateway returned error", {
-        status: response.status,
-        body: bodyError ? undefined : body,
-        url,
-      });
+      event.ok = false;
+      event.responseBody = bodyError ? undefined : body;
+      this.logger.error("create sandbox", event);
       return;
     }
 
     const [parseError, data] = await tryCatch(response.json());
 
     if (parseError) {
-      this.logger.error("Failed to parse gateway response", { error: parseError });
+      event.ok = false;
+      event.error = parseError instanceof Error ? parseError.message : String(parseError);
+      event.errorType = "parse";
+      this.logger.error("create sandbox", event);
       return;
     }
 
-    this.logger.debug("create succeeded", { sandboxId: data.id, runnerId });
+    event.ok = true;
+    event.sandboxId = data.id;
+    this.logger.log("create sandbox", event);
   }
 }