feat: system/http/traefik collectors and docker auto-discovery (M3)

Adds the remaining monitor types: a systeminformation-backed system
widget (single-flight cached so multiple widgets don't force
concurrent samples), an http widget with per-widget consecutive-
failure tracking, and a traefik widget that reads router/entrypoint/
middleware status from Traefik's own API. Also adds opt-in label-based
docker auto-discovery (discovery.docker in config.yml): containers
carrying traefik.enable=true are turned into docker widgets in a
synthetic "Discovered" group, re-scanned on a timer and whenever
config.yml changes, with manual widgets always taking precedence over
a discovered one for the same container.

Fixes a real bug surfaced while testing discovery: Next's App Router
bundles app/** through its own compiler pass, separate from server.ts
(run directly via tsx), so configStore/effectiveConfigStore were
silently instantiated twice - one instance watched and updated by
server.ts, another frozen instance read by SSR. Live config edits were
never reflected on page load without a full process restart. Both
stores now key their singleton off globalThis, which both module
graphs share within the same process.

Verified against a real Traefik v3 container (API-driven router list,
ping-based http check) and a labeled nginx container (auto-discovery),
including that a config.yml edit now shows up in a fresh page load
without restarting the server, in both dev and the production build.

components/widgets/http/Widget.tsx

@@ -0,0 +1,38 @@
+"use client";
+
+import type { Widget } from "@/lib/config/schema";
+import { useWidgetSubscription } from "@/lib/ws/client";
+
+type HttpWidget = Extract<Widget, { type: "http" }>;
+
+function statusColor(up: boolean | undefined, consecutiveFailures: number): string {
+  if (up === undefined) return "bg-fg-muted";
+  if (up) return "bg-status-up";
+  return consecutiveFailures > 2 ? "bg-status-down" : "bg-status-degraded";
+}
+
+export function HttpWidget({ widget, widgetId }: { widget: HttpWidget; widgetId: string }) {
+  const result = useWidgetSubscription(widgetId);
+  const data = result?.type === "http" ? result.data : null;
+  const errorMessage = result?.type === "error" ? result.message : null;
+
+  return (
+    <div className="flex flex-col gap-2 rounded-[var(--radius-widget)] border border-border bg-surface p-4">
+      <div className="flex items-center justify-between gap-2">
+        <span className="text-sm font-medium text-fg">{widget.name}</span>
+        <span
+          className={`h-2.5 w-2.5 shrink-0 rounded-full ${statusColor(data?.up, data?.consecutiveFailures ?? 0)}`}
+          title={data ? (data.up ? "up" : `down (${data.consecutiveFailures} checks failed)`) : "unknown"}
+        />
+      </div>
+      {errorMessage && <span className="text-xs text-status-down">{errorMessage}</span>}
+      {data && (
+        <dl className="flex flex-col gap-1 text-xs text-fg-muted">
+          <div>Status: {data.statusCode ?? "—"}</div>
+          <div>Latency: {data.latencyMs}ms</div>
+          {!data.up && data.error && <div className="text-status-down">{data.error}</div>}
+        </dl>
+      )}
+    </div>
+  );
+}

components/widgets/registry.ts

@@ -4,6 +4,9 @@ import { BookmarkWidget } from "./bookmark/Widget";
 import { SearchWidget } from "./search/Widget";
 import { DockerWidget } from "./docker/Widget";
 import { DatabaseWidget } from "./database/Widget";
+import { SystemWidget } from "./system/Widget";
+import { HttpWidget } from "./http/Widget";
+import { TraefikWidget } from "./traefik/Widget";
 
 type WidgetComponent<T extends Widget["type"]> = ComponentType<{
   widget: Extract<Widget, { type: T }>;
@@ -15,4 +18,7 @@ export const widgetRegistry: { [K in Widget["type"]]: WidgetComponent<K> } = {
   search: SearchWidget,
   docker: DockerWidget,
   database: DatabaseWidget,
+  system: SystemWidget,
+  http: HttpWidget,
+  traefik: TraefikWidget,
 };

components/widgets/system/Widget.tsx

@@ -0,0 +1,62 @@
+"use client";
+
+import type { Widget } from "@/lib/config/schema";
+import { useWidgetSubscription } from "@/lib/ws/client";
+import { formatBytes } from "@/lib/format";
+
+type SystemWidget = Extract<Widget, { type: "system" }>;
+
+function usagePercent(used: number, total: number): number {
+  return total > 0 ? Math.min(100, (used / total) * 100) : 0;
+}
+
+function UsageBar({ label, percent, detail }: { label: string; percent: number; detail: string }) {
+  return (
+    <div className="flex flex-col gap-1">
+      <div className="flex items-center justify-between text-xs text-fg-muted">
+        <span>{label}</span>
+        <span>{detail}</span>
+      </div>
+      <div className="h-1.5 w-full overflow-hidden rounded-full bg-surface-raised">
+        <div
+          className="h-full rounded-full bg-accent"
+          style={{ width: `${percent}%` }}
+        />
+      </div>
+    </div>
+  );
+}
+
+export function SystemWidget({ widget, widgetId }: { widget: SystemWidget; widgetId: string }) {
+  const result = useWidgetSubscription(widgetId);
+  const data = result?.type === "system" ? result.data : null;
+  const errorMessage = result?.type === "error" ? result.message : null;
+
+  return (
+    <div className="flex flex-col gap-3 rounded-[var(--radius-widget)] border border-border bg-surface p-4 sm:col-span-2">
+      <span className="text-sm font-medium text-fg">{widget.name}</span>
+      {errorMessage && <span className="text-xs text-status-down">{errorMessage}</span>}
+      {data && (
+        <div className="flex flex-col gap-2">
+          <UsageBar label="CPU" percent={data.cpuPercent} detail={`${data.cpuPercent.toFixed(1)}%`} />
+          <UsageBar
+            label="Memory"
+            percent={usagePercent(data.memUsedBytes, data.memTotalBytes)}
+            detail={`${formatBytes(data.memUsedBytes)} / ${formatBytes(data.memTotalBytes)}`}
+          />
+          <UsageBar
+            label="Disk"
+            percent={usagePercent(data.diskUsedBytes, data.diskTotalBytes)}
+            detail={`${formatBytes(data.diskUsedBytes)} / ${formatBytes(data.diskTotalBytes)}`}
+          />
+          <div className="flex items-center justify-between text-xs text-fg-muted">
+            <span>Network</span>
+            <span>
+              ↓ {formatBytes(data.netRxBytesPerSec)}/s · ↑ {formatBytes(data.netTxBytesPerSec)}/s
+            </span>
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}

components/widgets/traefik/Widget.tsx

@@ -0,0 +1,46 @@
+"use client";
+
+import type { Widget } from "@/lib/config/schema";
+import { useWidgetSubscription } from "@/lib/ws/client";
+
+type TraefikWidget = Extract<Widget, { type: "traefik" }>;
+
+export function TraefikWidget({ widget, widgetId }: { widget: TraefikWidget; widgetId: string }) {
+  const result = useWidgetSubscription(widgetId);
+  const data = result?.type === "traefik" ? result.data : null;
+  const errorMessage = result?.type === "error" ? result.message : null;
+
+  return (
+    <div className="flex flex-col gap-3 rounded-[var(--radius-widget)] border border-border bg-surface p-4 sm:col-span-2">
+      <div className="flex items-center justify-between">
+        <span className="text-sm font-medium text-fg">{widget.name}</span>
+        {data && (
+          <span className="text-xs text-fg-muted">
+            {data.entrypoints.map((ep) => ep.address).join(" · ") || `${data.entrypoints.length} entrypoints`}
+          </span>
+        )}
+      </div>
+      {errorMessage && <span className="text-xs text-status-down">{errorMessage}</span>}
+      {data && (
+        <div className="flex flex-col gap-1">
+          {data.routers.map((router) => (
+            <div key={router.name} className="flex items-center justify-between gap-2 text-xs">
+              <span className="truncate text-fg" title={router.rule}>
+                {router.name.replace(/@.*$/, "")}
+              </span>
+              <span className="flex items-center gap-1 text-fg-muted">
+                {router.tls && <span title="TLS enabled">🔒</span>}
+                <span
+                  className={router.status === "enabled" ? "text-status-up" : "text-status-down"}
+                >
+                  {router.status}
+                </span>
+              </span>
+            </div>
+          ))}
+          <span className="pt-1 text-xs text-fg-muted">{data.middlewaresCount} middlewares</span>
+        </div>
+      )}
+    </div>
+  );
+}