Emdash source with visual editor image upload fix

Fixes:
1. media.ts: wrap placeholder generation in try-catch
2. toolbar.ts: check r.ok, display error message in popover

infra/perf-monitor/src/events.ts

@@ -0,0 +1,59 @@
+/**
+ * Type definitions for Cloudflare event subscription messages.
+ * See: https://developers.cloudflare.com/queues/event-subscriptions/events-schemas/
+ */
+
+/** Workers Builds `build.succeeded` event. */
+export interface BuildSucceededEvent {
+	type: "cf.workersBuilds.worker.build.succeeded";
+	source: {
+		type: "workersBuilds.worker";
+		workerName: string;
+	};
+	payload: {
+		buildUuid: string;
+		status: "success";
+		buildOutcome: "success";
+		createdAt: string;
+		initializingAt: string;
+		runningAt: string;
+		stoppedAt: string;
+		buildTriggerMetadata: {
+			buildTriggerSource: string;
+			branch: string;
+			commitHash: string;
+			commitMessage: string;
+			author: string;
+			buildCommand: string;
+			deployCommand: string;
+			rootDirectory: string;
+			repoName: string;
+			providerAccountName: string;
+			providerType: string;
+		};
+	};
+	metadata: {
+		accountId: string;
+		eventSubscriptionId: string;
+		eventSchemaVersion: number;
+		eventTimestamp: string;
+	};
+}
+
+/**
+ * Other event types we may receive from the subscription but ignore.
+ * Kept loose (string `type`) so we don't block on schema updates.
+ */
+export interface UnknownEvent {
+	type: string;
+	source?: unknown;
+	payload?: unknown;
+	metadata?: unknown;
+}
+
+export type PerfQueueMessage = BuildSucceededEvent | UnknownEvent;
+
+/** Type guard for the only event we actually act on. */
+export function isBuildSucceeded(event: PerfQueueMessage): event is BuildSucceededEvent {
+	return event.type === "cf.workersBuilds.worker.build.succeeded";
+}