chat-messages: add timeline tool registry with HITL-aware fallback.

surfsense_web/features/chat-messages/timeline/tool-registry/fallback/fallback-tool-body.tsx

@@ -0,0 +1,41 @@
+"use client";
+
+import {
+	DoomLoopApproval,
+	GenericHitlApproval,
+	type InterruptResult,
+	isDoomLoopInterrupt,
+	isInterruptResult,
+} from "@/features/chat-messages/hitl";
+import type { TimelineToolComponent } from "../types";
+import { DefaultFallbackCard } from "./default-fallback-card";
+
+/**
+ * Mounted by the timeline for any tool name not in the registry. The
+ * fallback owns the inner discrimination between HITL approval cards
+ * and the default visual card:
+ *
+ *   isInterruptResult(result) ─┬─ isDoomLoopInterrupt → DoomLoopApproval
+ *                              └─ otherwise           → GenericHitlApproval
+ *   else                                              → DefaultFallbackCard
+ *
+ * This is the ONLY place ``isInterruptResult`` is checked for unknown
+ * tools. Per-tool components in ``components/tool-ui/*`` perform their
+ * own internal discrimination over richer result shapes; the fallback
+ * only knows the two top-level branches.
+ */
+export const FallbackToolBody: TimelineToolComponent = (props) => {
+	if (isInterruptResult(props.result)) {
+		const approvalProps = {
+			toolCallId: props.toolCallId,
+			toolName: props.toolName,
+			args: props.args,
+			result: props.result as InterruptResult,
+		};
+		if (isDoomLoopInterrupt(props.result)) {
+			return <DoomLoopApproval {...approvalProps} />;
+		}
+		return <GenericHitlApproval {...approvalProps} />;
+	}
+	return <DefaultFallbackCard {...props} />;
+};