feat(web): monitors list/detail/form UI

web/app/monitors/[id]/page.tsx

@@ -0,0 +1,236 @@
+"use client";
+
+import { useState } from "react";
+import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
+import { useParams, useRouter } from "next/navigation";
+import Link from "next/link";
+import { api, Monitor, MonitorStatus, Rollup } from "@/lib/api";
+import { Badge, Button, Card, CardHeader, CardTitle, Table, Thead, Tbody, Tr, Th, Td } from "@/components/ui";
+
+function statusVariant(status: MonitorStatus) {
+  switch (status) {
+    case "up":
+      return "success";
+    case "down":
+      return "danger";
+    default:
+      return "warning";
+  }
+}
+
+function uptimePct(rollups: Rollup[]): number {
+  const checks = rollups.reduce((a, r) => a + r.checks, 0);
+  const up = rollups.reduce((a, r) => a + r.up_count, 0);
+  return checks > 0 ? (up / checks) * 100 : 0;
+}
+
+function Heartbeat({ rollups }: { rollups: Rollup[] }) {
+  const recent = rollups.slice(-48);
+  return (
+    <div className="flex items-end gap-0.5">
+      {recent.map((r) => {
+        const pct = r.checks > 0 ? (r.up_count / r.checks) * 100 : 0;
+        const color = r.checks === 0 ? "bg-surface-2" : pct >= 99 ? "bg-success" : pct >= 80 ? "bg-warning" : "bg-danger";
+        return (
+          <div
+            key={r.period_start}
+            className={`h-8 w-1.5 rounded-sm ${color}`}
+            title={`${new Date(r.period_start).toLocaleString()} — ${pct.toFixed(0)}% up`}
+          />
+        );
+      })}
+      {recent.length === 0 && <span className="text-xs text-text-secondary">No history yet.</span>}
+    </div>
+  );
+}
+
+export default function MonitorDetailPage() {
+  const params = useParams();
+  const router = useRouter();
+  const queryClient = useQueryClient();
+  const monitorId = params.id as string;
+  const [confirmDelete, setConfirmDelete] = useState(false);
+
+  const { data: monitor, isLoading } = useQuery({
+    queryKey: ["monitors", monitorId],
+    queryFn: () => api.getMonitor(monitorId),
+    refetchInterval: 30_000,
+  });
+
+  const { data: rollups } = useQuery({
+    queryKey: ["monitors", monitorId, "uptime"],
+    queryFn: () => api.getMonitorUptime(monitorId),
+    refetchInterval: 60_000,
+  });
+
+  const { data: incidents } = useQuery({
+    queryKey: ["monitors", monitorId, "incidents"],
+    queryFn: () => api.getMonitorIncidents(monitorId),
+    refetchInterval: 60_000,
+  });
+
+  const { mutate: deleteMonitor, isPending: isDeleting } = useMutation({
+    mutationFn: () => api.deleteMonitor(monitorId),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["monitors"] });
+      router.push("/monitors");
+    },
+  });
+
+  const { mutate: toggleEnabled } = useMutation({
+    mutationFn: (enabled: boolean) => api.updateMonitor(monitorId, { enabled }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ["monitors", monitorId] }),
+  });
+
+  if (isLoading) {
+    return (
+      <div className="flex h-full items-center justify-center">
+        <div className="h-8 w-8 animate-spin rounded-full border-2 border-border border-t-accent" />
+      </div>
+    );
+  }
+
+  if (!monitor) {
+    return (
+      <div className="p-8">
+        <div className="rounded-lg border border-danger/30 bg-danger/10 p-4 text-danger">Monitor not found.</div>
+      </div>
+    );
+  }
+
+  const all = rollups ?? [];
+  const last24 = all.slice(-24);
+
+  return (
+    <div className="p-8">
+      <div className="mb-6 flex items-start justify-between">
+        <div>
+          <Link href="/monitors" className="text-sm text-text-secondary hover:text-text-primary">
+            ← Monitors
+          </Link>
+          <div className="mt-2 flex items-center gap-3">
+            <h1 className="text-2xl font-bold text-text-primary">{monitor.name}</h1>
+            <Badge variant={statusVariant(monitor.state.status)}>{monitor.state.status}</Badge>
+            <Badge variant="neutral">{monitor.type}</Badge>
+            {!monitor.enabled && <Badge variant="warning">disabled</Badge>}
+          </div>
+          {monitor.state.message && <p className="mt-1 text-sm text-text-secondary">{monitor.state.message}</p>}
+        </div>
+        <div className="flex gap-2">
+          <Button variant="secondary" onClick={() => toggleEnabled(!monitor.enabled)}>
+            {monitor.enabled ? "Disable" : "Enable"}
+          </Button>
+          {!confirmDelete ? (
+            <Button variant="danger" onClick={() => setConfirmDelete(true)}>
+              Delete
+            </Button>
+          ) : (
+            <div className="flex items-center gap-2">
+              <span className="text-sm text-danger">Are you sure?</span>
+              <Button variant="danger" loading={isDeleting} onClick={() => deleteMonitor()}>
+                Confirm
+              </Button>
+              <Button variant="ghost" onClick={() => setConfirmDelete(false)}>
+                Cancel
+              </Button>
+            </div>
+          )}
+        </div>
+      </div>
+
+      <div className="mb-6 grid grid-cols-2 gap-4 sm:grid-cols-4">
+        <Card>
+          <p className="text-xs text-text-secondary">Uptime (24h)</p>
+          <p className="mt-1 text-2xl font-bold text-text-primary">{uptimePct(last24).toFixed(1)}%</p>
+        </Card>
+        <Card>
+          <p className="text-xs text-text-secondary">Uptime (30d)</p>
+          <p className="mt-1 text-2xl font-bold text-text-primary">{uptimePct(all).toFixed(1)}%</p>
+        </Card>
+        <Card>
+          <p className="text-xs text-text-secondary">Latency</p>
+          <p className="mt-1 text-2xl font-bold text-text-primary">{monitor.state.latency_ms}ms</p>
+        </Card>
+        <Card>
+          <p className="text-xs text-text-secondary">Cert expiry</p>
+          <p className="mt-1 text-sm font-medium text-text-primary">
+            {monitor.state.cert_expiry_at ? new Date(monitor.state.cert_expiry_at).toLocaleDateString() : "—"}
+          </p>
+        </Card>
+      </div>
+
+      <Card className="mb-6">
+        <CardHeader>
+          <CardTitle>Heartbeat (last 48h)</CardTitle>
+        </CardHeader>
+        <Heartbeat rollups={all} />
+      </Card>
+
+      <div className="grid grid-cols-1 gap-6 lg:grid-cols-2">
+        <Card padding={false}>
+          <div className="border-b border-border px-6 py-4">
+            <h2 className="text-lg font-semibold text-text-primary">Incidents</h2>
+          </div>
+          {!incidents || incidents.length === 0 ? (
+            <div className="py-12 text-center text-sm text-text-secondary">No incidents recorded.</div>
+          ) : (
+            <Table>
+              <Thead>
+                <Tr>
+                  <Th>Started</Th>
+                  <Th>Resolved</Th>
+                  <Th>Cause</Th>
+                </Tr>
+              </Thead>
+              <Tbody>
+                {incidents.map((inc) => (
+                  <Tr key={inc.incident_id}>
+                    <Td>
+                      <span className="text-xs text-text-secondary">{new Date(inc.started_at).toLocaleString()}</span>
+                    </Td>
+                    <Td>
+                      {inc.resolved_at ? (
+                        <span className="text-xs text-text-secondary">{new Date(inc.resolved_at).toLocaleString()}</span>
+                      ) : (
+                        <Badge variant="danger">ongoing</Badge>
+                      )}
+                    </Td>
+                    <Td>
+                      <span className="text-xs text-text-primary">{inc.cause || "—"}</span>
+                    </Td>
+                  </Tr>
+                ))}
+              </Tbody>
+            </Table>
+          )}
+        </Card>
+
+        <Card>
+          <CardHeader>
+            <CardTitle>Configuration</CardTitle>
+          </CardHeader>
+          <dl className="space-y-3 text-sm">
+            <div>
+              <dt className="text-text-secondary">Runner</dt>
+              <dd className="mt-0.5 font-mono text-text-primary">{monitor.runner}</dd>
+            </div>
+            <div className="border-t border-border pt-3">
+              <dt className="text-text-secondary">Interval</dt>
+              <dd className="mt-0.5 text-text-primary">{monitor.interval_sec}s</dd>
+            </div>
+            <div className="border-t border-border pt-3">
+              <dt className="text-text-secondary">Retries before down</dt>
+              <dd className="mt-0.5 text-text-primary">{monitor.retries}</dd>
+            </div>
+            <div className="border-t border-border pt-3">
+              <dt className="text-text-secondary">Target</dt>
+              <dd className="mt-0.5 font-mono text-xs text-text-primary break-all">
+                {monitor.target.url || `${monitor.target.host ?? ""}${monitor.target.port ? `:${monitor.target.port}` : ""}`}
+              </dd>
+            </div>
+          </dl>
+        </Card>
+      </div>
+    </div>
+  );
+}

web/app/monitors/new/page.tsx

@@ -0,0 +1,189 @@
+"use client";
+
+import { useState } from "react";
+import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
+import { useRouter } from "next/navigation";
+import Link from "next/link";
+import { api, MonitorInput, MonitorType } from "@/lib/api";
+import { Button, Card } from "@/components/ui";
+
+const inputClass =
+  "w-full rounded-lg border border-border bg-surface-2 px-3 py-2 text-sm text-text-primary placeholder:text-text-tertiary focus:border-accent/50 focus:outline-none focus:ring-1 focus:ring-accent/30";
+
+const labelClass = "mb-1.5 block text-sm font-medium text-text-secondary";
+
+export default function NewMonitorPage() {
+  const router = useRouter();
+  const queryClient = useQueryClient();
+
+  const [name, setName] = useState("");
+  const [type, setType] = useState<MonitorType>("http");
+  const [url, setUrl] = useState("");
+  const [host, setHost] = useState("");
+  const [port, setPort] = useState<number>(443);
+  const [method, setMethod] = useState("GET");
+  const [expectedStatus, setExpectedStatus] = useState<number>(200);
+  const [keyword, setKeyword] = useState("");
+  const [tlsWarnDays, setTlsWarnDays] = useState<number>(14);
+  const [intervalSec, setIntervalSec] = useState<number>(60);
+  const [retries, setRetries] = useState<number>(1);
+  const [runner, setRunner] = useState("server");
+  const [enabled, setEnabled] = useState(true);
+
+  const { data: servers } = useQuery({ queryKey: ["servers"], queryFn: () => api.listServers() });
+
+  const { mutate: create, isPending, error } = useMutation({
+    mutationFn: (input: MonitorInput) => api.createMonitor(input),
+    onSuccess: (m) => {
+      queryClient.invalidateQueries({ queryKey: ["monitors"] });
+      router.push(`/monitors/${m.monitor_id}`);
+    },
+  });
+
+  function handleSubmit(e: React.FormEvent) {
+    e.preventDefault();
+    const target: MonitorInput["target"] = {};
+    if (type === "http") {
+      target.url = url;
+      target.method = method;
+      target.expected_status = expectedStatus;
+      if (keyword) target.keyword = keyword;
+    } else if (type === "tls") {
+      target.host = host;
+      target.port = port || 443;
+      target.tls_warn_days = tlsWarnDays;
+    } else if (type === "icmp") {
+      target.host = host;
+    } else {
+      target.host = host;
+      target.port = port;
+    }
+    create({ name, type, target, interval_sec: intervalSec, retries, runner, enabled });
+  }
+
+  return (
+    <div className="p-8">
+      <Link href="/monitors" className="text-sm text-text-secondary hover:text-text-primary">
+        ← Monitors
+      </Link>
+      <h1 className="mb-6 mt-2 text-2xl font-bold text-text-primary">New Monitor</h1>
+
+      <Card className="max-w-2xl">
+        <form onSubmit={handleSubmit} className="space-y-4">
+          <div>
+            <label className={labelClass}>Name</label>
+            <input className={inputClass} value={name} onChange={(e) => setName(e.target.value)} placeholder="e.g. API health" required />
+          </div>
+
+          <div>
+            <label className={labelClass}>Type</label>
+            <div className="grid grid-cols-4 gap-2">
+              {(["http", "tcp", "icmp", "tls"] as const).map((t) => (
+                <button
+                  key={t}
+                  type="button"
+                  onClick={() => setType(t)}
+                  className={`rounded-lg border px-3 py-2 text-sm font-medium transition-colors ${
+                    type === t ? "border-accent bg-accent/10 text-accent" : "border-border bg-surface-2 text-text-secondary hover:border-accent/40 hover:text-text-primary"
+                  }`}
+                >
+                  {t.toUpperCase()}
+                </button>
+              ))}
+            </div>
+          </div>
+
+          {type === "http" && (
+            <>
+              <div>
+                <label className={labelClass}>URL</label>
+                <input className={inputClass} value={url} onChange={(e) => setUrl(e.target.value)} placeholder="https://example.com/health" required />
+              </div>
+              <div className="grid grid-cols-2 gap-4">
+                <div>
+                  <label className={labelClass}>Method</label>
+                  <select className={inputClass} value={method} onChange={(e) => setMethod(e.target.value)}>
+                    <option>GET</option>
+                    <option>HEAD</option>
+                  </select>
+                </div>
+                <div>
+                  <label className={labelClass}>Expected status</label>
+                  <input type="number" className={inputClass} value={expectedStatus} onChange={(e) => setExpectedStatus(Number(e.target.value))} />
+                </div>
+              </div>
+              <div>
+                <label className={labelClass}>Keyword (optional, body must contain)</label>
+                <input className={inputClass} value={keyword} onChange={(e) => setKeyword(e.target.value)} placeholder="e.g. ok" />
+              </div>
+            </>
+          )}
+
+          {(type === "tcp" || type === "tls" || type === "icmp") && (
+            <div className="grid grid-cols-2 gap-4">
+              <div>
+                <label className={labelClass}>Host</label>
+                <input className={inputClass} value={host} onChange={(e) => setHost(e.target.value)} placeholder="example.com" required />
+              </div>
+              {type !== "icmp" && (
+                <div>
+                  <label className={labelClass}>Port</label>
+                  <input type="number" className={inputClass} value={port} onChange={(e) => setPort(Number(e.target.value))} />
+                </div>
+              )}
+            </div>
+          )}
+
+          {type === "tls" && (
+            <div>
+              <label className={labelClass}>Warn days before expiry</label>
+              <input type="number" className={inputClass} value={tlsWarnDays} onChange={(e) => setTlsWarnDays(Number(e.target.value))} />
+            </div>
+          )}
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className={labelClass}>Interval (seconds)</label>
+              <input type="number" className={inputClass} value={intervalSec} onChange={(e) => setIntervalSec(Number(e.target.value))} min={10} />
+            </div>
+            <div>
+              <label className={labelClass}>Retries before down</label>
+              <input type="number" className={inputClass} value={retries} onChange={(e) => setRetries(Number(e.target.value))} min={1} />
+            </div>
+          </div>
+
+          <div>
+            <label className={labelClass}>Runner</label>
+            <select className={inputClass} value={runner} onChange={(e) => setRunner(e.target.value)}>
+              <option value="server">Server (central)</option>
+              {servers?.map((s) => (
+                <option key={s.server_id} value={s.server_id}>
+                  Agent · {s.hostname}
+                </option>
+              ))}
+            </select>
+            <p className="mt-1 text-xs text-text-tertiary">Agent-run monitors require the agent monitor scheduler (P2).</p>
+          </div>
+
+          <label className="flex items-center gap-2 text-sm text-text-secondary">
+            <input type="checkbox" checked={enabled} onChange={(e) => setEnabled(e.target.checked)} />
+            Enabled
+          </label>
+
+          {error && <p className="text-sm text-danger">{(error as Error).message}</p>}
+
+          <div className="flex gap-3 pt-1">
+            <Button type="submit" variant="primary" loading={isPending}>
+              Create Monitor
+            </Button>
+            <Link href="/monitors">
+              <Button type="button" variant="ghost">
+                Cancel
+              </Button>
+            </Link>
+          </div>
+        </form>
+      </Card>
+    </div>
+  );
+}

web/app/monitors/page.tsx

@@ -0,0 +1,104 @@
+"use client";
+
+import { useQuery } from "@tanstack/react-query";
+import Link from "next/link";
+import { api, Monitor, MonitorStatus } from "@/lib/api";
+import { Badge, Button, Card, Table, Thead, Tbody, Tr, Th, Td } from "@/components/ui";
+
+function statusVariant(status: MonitorStatus) {
+  switch (status) {
+    case "up":
+      return "success";
+    case "down":
+      return "danger";
+    default:
+      return "warning";
+  }
+}
+
+function targetSummary(m: Monitor): string {
+  if (m.type === "http") return m.target.url ?? "";
+  if (m.type === "tls") return `${m.target.host ?? ""}:${m.target.port || 443}`;
+  if (m.type === "icmp") return m.target.host ?? "";
+  return `${m.target.host ?? ""}:${m.target.port ?? ""}`;
+}
+
+export default function MonitorsPage() {
+  const { data: monitors, isLoading } = useQuery({
+    queryKey: ["monitors"],
+    queryFn: () => api.listMonitors(),
+    refetchInterval: 30_000,
+  });
+
+  return (
+    <div className="p-8">
+      <div className="mb-6 flex items-center justify-between">
+        <div>
+          <h1 className="text-2xl font-bold text-text-primary">Monitors</h1>
+          <p className="mt-1 text-sm text-text-secondary">Service uptime and latency checks.</p>
+        </div>
+        <Link href="/monitors/new">
+          <Button variant="primary">New Monitor</Button>
+        </Link>
+      </div>
+
+      <Card padding={false}>
+        {isLoading ? (
+          <div className="flex justify-center py-16">
+            <div className="h-8 w-8 animate-spin rounded-full border-2 border-border border-t-accent" />
+          </div>
+        ) : !monitors || monitors.length === 0 ? (
+          <div className="py-16 text-center">
+            <p className="text-sm text-text-secondary">No monitors yet.</p>
+            <Link href="/monitors/new">
+              <Button variant="secondary" size="sm" className="mt-3">
+                Create your first monitor
+              </Button>
+            </Link>
+          </div>
+        ) : (
+          <Table>
+            <Thead>
+              <Tr>
+                <Th>Name</Th>
+                <Th>Type</Th>
+                <Th>Target</Th>
+                <Th>Status</Th>
+                <Th>Latency</Th>
+                <Th>Last check</Th>
+              </Tr>
+            </Thead>
+            <Tbody>
+              {monitors.map((m) => (
+                <Tr key={m.monitor_id}>
+                  <Td>
+                    <Link href={`/monitors/${m.monitor_id}`} className="font-medium text-text-primary hover:text-accent">
+                      {m.name}
+                    </Link>
+                  </Td>
+                  <Td>
+                    <Badge variant="neutral">{m.type}</Badge>
+                  </Td>
+                  <Td>
+                    <span className="font-mono text-xs text-text-secondary">{targetSummary(m)}</span>
+                  </Td>
+                  <Td>
+                    <Badge variant={statusVariant(m.state.status)}>{m.state.status}</Badge>
+                  </Td>
+                  <Td>
+                    <span className="text-sm text-text-secondary">{m.state.latency_ms}ms</span>
+                  </Td>
+                  <Td>
+                    <span className="text-xs text-text-secondary">
+                      {m.state.last_check_at ? new Date(m.state.last_check_at).toLocaleTimeString() : "—"}
+                    </span>
+                  </Td>
+                </Tr>
+              ))}
+            </Tbody>
+          </Table>
+        )}
+      </Card>
+    </div>
+  );
+}

web/components/Sidebar.tsx

@@ -60,6 +60,14 @@ function SettingsIcon() {
   );
 }
 
+function MonitorIcon() {
+  return (
+    <svg className="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
+      <path strokeLinecap="round" strokeLinejoin="round" d="M3 12h4l2 6 4-14 2 8h6" />
+    </svg>
+  );
+}
+
 function StepsIcon() {
   return (
     <svg className="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
@@ -70,6 +78,7 @@ function StepsIcon() {
 
 const navItems: NavItem[] = [
   { href: "/servers", label: "Servers", icon: <ServerIcon /> },
+  { href: "/monitors", label: "Monitors", icon: <MonitorIcon /> },
   { href: "/keys", label: "SSH Keys", icon: <KeyIcon /> },
   { href: "/secrets", label: "Secrets", icon: <SecretIcon /> },
   { href: "/workflows", label: "Workflows", icon: <WorkflowIcon /> },

web/lib/api.ts

@@ -34,6 +34,69 @@ export interface Server {
   inventory?: Inventory;
 }
 
+export type MonitorType = "http" | "tcp" | "icmp" | "tls";
+export type MonitorStatus = "up" | "down" | "pending";
+
+export interface MonitorTarget {
+  url?: string;
+  host?: string;
+  port?: number;
+  method?: string;
+  expected_status?: number;
+  keyword?: string;
+  tls_warn_days?: number;
+}
+
+export interface MonitorState {
+  status: MonitorStatus;
+  last_check_at?: string;
+  latency_ms: number;
+  message?: string;
+  cert_expiry_at?: string;
+  fails: number;
+}
+
+export interface Monitor {
+  monitor_id: string;
+  name: string;
+  type: MonitorType;
+  target: MonitorTarget;
+  interval_sec: number;
+  runner: string; // "server" or a server_id
+  retries: number;
+  enabled: boolean;
+  channel_ids?: string[];
+  state: MonitorState;
+  created_at: string;
+}
+
+export interface MonitorInput {
+  name: string;
+  type: MonitorType;
+  target: MonitorTarget;
+  interval_sec: number;
+  runner: string;
+  retries: number;
+  enabled: boolean;
+  channel_ids?: string[];
+}
+
+export interface Incident {
+  incident_id: string;
+  monitor_id: string;
+  started_at: string;
+  resolved_at?: string;
+  cause?: string;
+}
+
+export interface Rollup {
+  monitor_id: string;
+  period_start: string;
+  checks: number;
+  up_count: number;
+  sum_latency: number;
+}
+
 export interface ConsoleConnectRequest {
   server_id: string;
   protocol: string;
@@ -278,6 +341,35 @@ export const api = {
     return `curl -fsSL "${window.location.origin}/update" | bash`;
   },
 
+  // Monitors
+  listMonitors(): Promise<Monitor[]> {
+    return request<Monitor[]>("/monitors");
+  },
+
+  getMonitor(monitorId: string): Promise<Monitor> {
+    return request<Monitor>(`/monitors/${monitorId}`);
+  },
+
+  createMonitor(input: MonitorInput): Promise<Monitor> {
+    return request<Monitor>("/monitors", { method: "POST", body: JSON.stringify(input) });
+  },
+
+  updateMonitor(monitorId: string, input: Partial<MonitorInput>): Promise<void> {
+    return request<void>(`/monitors/${monitorId}`, { method: "PUT", body: JSON.stringify(input) });
+  },
+
+  deleteMonitor(monitorId: string): Promise<void> {
+    return request<void>(`/monitors/${monitorId}`, { method: "DELETE" });
+  },
+
+  getMonitorIncidents(monitorId: string): Promise<Incident[]> {
+    return request<Incident[]>(`/monitors/${monitorId}/incidents`);
+  },
+
+  getMonitorUptime(monitorId: string): Promise<Rollup[]> {
+    return request<Rollup[]>(`/monitors/${monitorId}/uptime`);
+  },
+
   getLatestAgentVersion(): Promise<{ version: string }> {
     return request<{ version: string }>("/agent/latest-version");
   },