feat: add health indicator and localhost auto-detect

Surfaces live connection health for the active instance in the sidebar
and probes localhost:8000 on the first-run choose-type screen so users
running Honcho locally can connect in one tap.

- useHealthStatus hook polls checkConnection every 30s via TanStack Query
- HealthDot component renders a colored status dot with tooltip
- choose-type screen silently probes http://localhost:8000 once; on
  success it surfaces a "Detected Honcho at localhost:8000 — tap to
  connect" banner that opens the self-hosted form

packages/web/src/components/layout/Sidebar.tsx

@@ -13,7 +13,9 @@ import {
 	Sun,
 } from "lucide-react";
 import { useEffect, useRef, useState } from "react";
+import { HealthDot } from "@/components/shared/HealthDot";
 import { useDemo } from "@/hooks/useDemo";
+import { useHealthStatus } from "@/hooks/useHealthStatus";
 import { useInstances } from "@/hooks/useInstances";
 import { useTheme } from "@/hooks/useTheme";
 import { COLOR } from "@/lib/constants";
@@ -29,6 +31,7 @@ export function Sidebar() {
 	const { instances, active, activate } = useInstances();
 	const { theme, toggle } = useTheme();
 	const { demo, toggle: toggleDemo, mask } = useDemo();
+	const { data: health } = useHealthStatus();
 	const [switcherOpen, setSwitcherOpen] = useState(false);
 	const switcherRef = useRef<HTMLDivElement | null>(null);
 
@@ -87,8 +90,12 @@ export function Sidebar() {
 							title={mask(active.baseUrl)}
 						>
 							<div className="min-w-0 flex-1">
-								<p className="text-xs font-medium truncate" style={{ color: "var(--text-2)" }}>
-									{active.name}
+								<p
+									className="text-xs font-medium truncate flex items-center gap-1.5"
+									style={{ color: "var(--text-2)" }}
+								>
+									<HealthDot status={health?.status} message={health?.message} />
+									<span className="truncate">{active.name}</span>
 								</p>
 								<p className="text-xs font-mono truncate" style={{ color: "var(--text-4)" }}>
 									{mask(active.baseUrl.replace(/^https?:\/\//, ""))}

packages/web/src/components/settings/InstancesManager.tsx

@@ -1,13 +1,15 @@
-import { motion } from "framer-motion";
-import { Check, ChevronRight, Cloud, Pencil, Plus, Server, Trash2 } from "lucide-react";
-import { useState } from "react";
+import { AnimatePresence, motion } from "framer-motion";
+import { Check, ChevronRight, Cloud, Pencil, Plus, Server, Sparkles, Trash2 } from "lucide-react";
+import { useEffect, useState } from "react";
 import { type ConnectionPreset, SettingsForm } from "@/components/settings/SettingsForm";
 import { Button } from "@/components/ui/button";
 import { Muted } from "@/components/ui/typography";
 import { useInstances } from "@/hooks/useInstances";
-import { HONCHO_CLOUD_URL, type Instance, isCloudInstance } from "@/lib/config";
+import { checkConnection, HONCHO_CLOUD_URL, type Instance, isCloudInstance } from "@/lib/config";
 import { COLOR } from "@/lib/constants";
 
+const LOCALHOST_PROBE_URL = "http://localhost:8000";
+
 type Mode =
 	| { kind: "list" }
 	| { kind: "choose-type" }
@@ -99,6 +101,21 @@ interface ConnectionTypeChooserProps {
 }
 
 function ConnectionTypeChooser({ onPick, onCancel }: ConnectionTypeChooserProps) {
+	const [localhostDetected, setLocalhostDetected] = useState(false);
+
+	useEffect(() => {
+		let cancelled = false;
+		void checkConnection(LOCALHOST_PROBE_URL).then((result) => {
+			if (cancelled) return;
+			if (result.status === "ok" || result.status === "auth-required") {
+				setLocalhostDetected(true);
+			}
+		});
+		return () => {
+			cancelled = true;
+		};
+	}, []);
+
 	return (
 		<div
 			className="rounded-2xl p-6 space-y-3"
@@ -116,6 +133,35 @@ function ConnectionTypeChooser({ onPick, onCancel }: ConnectionTypeChooserProps)
 				</Muted>
 			</div>
 
+			<AnimatePresence>
+				{localhostDetected && (
+					<motion.button
+						type="button"
+						initial={{ opacity: 0, height: 0 }}
+						animate={{ opacity: 1, height: "auto" }}
+						exit={{ opacity: 0, height: 0 }}
+						onClick={() => onPick("self-hosted")}
+						className="w-full overflow-hidden rounded-xl p-3 flex items-center gap-2.5 text-left"
+						style={{
+							background: COLOR.successDim,
+							border: `1px solid ${COLOR.successBorder}`,
+						}}
+					>
+						<Sparkles
+							className="w-4 h-4 shrink-0"
+							style={{ color: COLOR.success }}
+							strokeWidth={1.5}
+						/>
+						<div className="min-w-0 flex-1">
+							<p className="text-xs font-medium" style={{ color: COLOR.success }}>
+								Detected Honcho at {LOCALHOST_PROBE_URL.replace(/^https?:\/\//, "")}
+							</p>
+							<Muted className="text-xs mt-0.5">Tap to connect to it</Muted>
+						</div>
+					</motion.button>
+				)}
+			</AnimatePresence>
+
 			<ConnectionTypeButton
 				icon={Cloud}
 				title="Honcho Cloud"

packages/web/src/components/shared/HealthDot.tsx

@@ -0,0 +1,48 @@
+import { motion } from "framer-motion";
+import type { HealthStatus } from "@/lib/config";
+import { COLOR } from "@/lib/constants";
+
+interface HealthDotProps {
+	status: HealthStatus | undefined;
+	message?: string;
+	size?: number;
+}
+
+const COLORS: Record<HealthStatus, string> = {
+	ok: COLOR.success,
+	"auth-required": COLOR.warning,
+	unreachable: COLOR.destructive,
+	checking: COLOR.accentText,
+};
+
+const LABELS: Record<HealthStatus, string> = {
+	ok: "Connected",
+	"auth-required": "Auth required",
+	unreachable: "Unreachable",
+	checking: "Checking...",
+};
+
+export function HealthDot({ status, message, size = 8 }: HealthDotProps) {
+	const color = status ? COLORS[status] : "var(--text-4)";
+	const label = status ? LABELS[status] : "Unknown";
+	const title = message ? `${label} — ${message}` : label;
+	const pulsing = status === "checking";
+
+	return (
+		<motion.span
+			aria-label={`Connection status: ${label}`}
+			title={title}
+			animate={pulsing ? { opacity: [0.4, 1, 0.4] } : { opacity: 1 }}
+			transition={pulsing ? { duration: 1.2, repeat: Number.POSITIVE_INFINITY } : undefined}
+			style={{
+				display: "inline-block",
+				width: size,
+				height: size,
+				borderRadius: "50%",
+				background: color,
+				boxShadow: status === "ok" ? `0 0 6px ${color}80` : undefined,
+				flexShrink: 0,
+			}}
+		/>
+	);
+}

packages/web/src/hooks/useHealthStatus.ts

@@ -0,0 +1,20 @@
+import { useQuery } from "@tanstack/react-query";
+import { useInstances } from "@/hooks/useInstances";
+import { checkConnection } from "@/lib/config";
+
+const POLL_INTERVAL_MS = 30_000;
+
+export function useHealthStatus() {
+	const { active } = useInstances();
+	return useQuery({
+		queryKey: ["health", active?.id, active?.baseUrl, active?.token],
+		queryFn: async () => {
+			if (!active) throw new Error("No active instance");
+			return checkConnection(active.baseUrl, active.token || undefined);
+		},
+		enabled: !!active,
+		refetchInterval: POLL_INTERVAL_MS,
+		refetchOnWindowFocus: true,
+		staleTime: 0,
+	});
+}

packages/web/src/test/health-status.test.tsx

@@ -0,0 +1,42 @@
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { renderHook, waitFor } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { useHealthStatus } from "@/hooks/useHealthStatus";
+import { saveStore } from "@/lib/config";
+
+const httpFetch = vi.hoisted(() => vi.fn());
+vi.mock("@/lib/http", () => ({ httpFetch }));
+
+function wrap(qc: QueryClient) {
+	return ({ children }: { children: React.ReactNode }) => (
+		<QueryClientProvider client={qc}>{children}</QueryClientProvider>
+	);
+}
+
+describe("useHealthStatus", () => {
+	beforeEach(() => {
+		httpFetch.mockReset();
+		localStorage.clear();
+	});
+
+	afterEach(() => {
+		localStorage.clear();
+	});
+
+	it("is disabled with no active instance", () => {
+		const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+		const { result } = renderHook(() => useHealthStatus(), { wrapper: wrap(qc) });
+		expect(result.current.fetchStatus).toBe("idle");
+	});
+
+	it("reports ok when the active instance responds 200", async () => {
+		saveStore({
+			instances: [{ id: "i1", name: "Local", baseUrl: "http://localhost:8000", token: "" }],
+			activeId: "i1",
+		});
+		httpFetch.mockResolvedValue(new Response("{}", { status: 200 }));
+		const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+		const { result } = renderHook(() => useHealthStatus(), { wrapper: wrap(qc) });
+		await waitFor(() => expect(result.current.data?.status).toBe("ok"));
+	});
+});