fix(dashboard): guard setMetricsById against same-value calls to end loop

Even with primitive useEffect deps, TanStack Query or React concurrent
rendering can cause onMetrics to fire with identical values mid-render-cycle.
Add a ref-based equality check in Dashboard.onMetrics: if all five metric
values are unchanged, skip setMetricsById entirely — no state update, no
Dashboard re-render, loop terminates.

Also fixes vi.fn<TFunction>() typing in server-workspace-rows.test.tsx to
satisfy tsc (Vitest 4 single-type-arg signature).

packages/web/src/components/dashboard/Dashboard.tsx

@@ -1,7 +1,7 @@
 import { Link, useNavigate } from "@tanstack/react-router";
 import { motion } from "framer-motion";
 import { Boxes, LayoutDashboard, Network, Settings as SettingsIcon } from "lucide-react";
-import { useCallback, useEffect, useMemo, useState } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import {
 	computeFleetAggregates,
 	DEFAULT_ROW_METRICS,
@@ -28,6 +28,7 @@ export function Dashboard() {
 	const navigate = useNavigate();
 	const [serverFilter, setServerFilter] = useState<string>(ALL_SERVERS);
 	const [metricsById, setMetricsById] = useState<Record<string, FleetRowMetrics>>({});
+	const lastMetrics = useRef<Record<string, FleetRowMetrics>>({});
 
 	useEffect(() => {
 		if (serverFilter !== ALL_SERVERS && !instances.find((i) => i.id === serverFilter)) {
@@ -36,6 +37,17 @@ export function Dashboard() {
 	}, [instances, serverFilter]);
 
 	const onMetrics = useCallback((id: string, m: FleetRowMetrics) => {
+		const prev = lastMetrics.current[id];
+		if (
+			prev &&
+			prev.workspaceCount === m.workspaceCount &&
+			prev.conclusionCount === m.conclusionCount &&
+			prev.queueActive === m.queueActive &&
+			prev.queuePending === m.queuePending &&
+			prev.health === m.health
+		)
+			return;
+		lastMetrics.current = { ...lastMetrics.current, [id]: m };
 		setMetricsById((prev) => ({ ...prev, [id]: m }));
 	}, []);
 

packages/web/src/test/server-workspace-rows.test.tsx

@@ -2,6 +2,7 @@ import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 import { act, render, waitFor } from "@testing-library/react";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { ServerWorkspaceRows } from "@/components/dashboard/ServerWorkspaceRows";
+import type { FleetRowMetrics } from "@/components/fleet/fleetAggregates";
 import { DemoProvider } from "@/context/DemoContext";
 import type { Instance } from "@/lib/config";
 
@@ -29,7 +30,7 @@ function makeQc() {
 	return new QueryClient({ defaultOptions: { queries: { retry: false, staleTime: Infinity } } });
 }
 
-function renderRows(instance: Instance, onMetrics: ReturnType<typeof vi.fn>) {
+function renderRows(instance: Instance, onMetrics: (id: string, metrics: FleetRowMetrics) => void) {
 	const qc = makeQc();
 	return render(
 		<QueryClientProvider client={qc}>
@@ -52,7 +53,7 @@ describe("ServerWorkspaceRows — onMetrics stability", () => {
 	afterEach(() => localStorage.clear());
 
 	it("calls onMetrics with health:ok after data loads", async () => {
-		const onMetrics = vi.fn();
+		const onMetrics = vi.fn<(id: string, m: FleetRowMetrics) => void>();
 		renderRows(neo, onMetrics);
 		await waitFor(() =>
 			expect(onMetrics).toHaveBeenCalledWith(
@@ -63,7 +64,7 @@ describe("ServerWorkspaceRows — onMetrics stability", () => {
 	});
 
 	it("does not call onMetrics again when values have not changed", async () => {
-		const onMetrics = vi.fn();
+		const onMetrics = vi.fn<(id: string, m: FleetRowMetrics) => void>();
 		renderRows(neo, onMetrics);
 
 		// Wait until we have at least one call with stable state
@@ -83,7 +84,7 @@ describe("ServerWorkspaceRows — onMetrics stability", () => {
 	});
 
 	it("calls onMetrics when health transitions from loading to ok", async () => {
-		const onMetrics = vi.fn();
+		const onMetrics = vi.fn<(id: string, m: FleetRowMetrics) => void>();
 		renderRows(neo, onMetrics);
 
 		// Must eventually report ok (not just loading)