Resources: subscriptions/listen model on modern servers (era fork) (#1630) (#1730)

Fork resource subscriptions by protocol era: legacy keeps resources/subscribe; modern (2026-07-28) models subscriptions as a filter over one long-lived subscriptions/listen stream with reconnect-by-re-listen (capped backoff), an optimistic Connecting→Listening header badge, and a fix so the browser proxy no longer blocks listen() ~60s. Closes #1630.

clients/web/src/components/screens/ResourcesScreen/ResourcesScreen.stories.tsx

@@ -239,6 +239,27 @@ export const SubscriptionsUnsupported: Story = {
   },
 };
 
+// Modern (2026-07-28) era: subscriptions ride one `subscriptions/listen`
+// stream, so the Subscriptions section shows a stream-status badge in its panel
+// and a status dot in its header (#1630).
+export const ModernSubscriptionStream: Story = {
+  args: {
+    resources: sampleResources,
+    templates: sampleTemplates,
+    subscriptions: sampleSubscriptions,
+    protocolEra: "modern",
+    subscriptionStreamState: {
+      active: true,
+      status: "acknowledged",
+      honoredUris: sampleSubscriptions.map((s) => s.resource.uri),
+    },
+  },
+  play: async ({ canvasElement }) => {
+    const canvas = within(canvasElement);
+    expect(await canvas.findByText("Listening")).toBeInTheDocument();
+  },
+};
+
 const manyResources: Resource[] = Array.from({ length: 40 }, (_, i) => ({
   name: `resource-${String(i + 1).padStart(2, "0")}.wav`,
   uri: `file:///kit/resource-${i + 1}.wav`,

clients/web/src/components/screens/ResourcesScreen/ResourcesScreen.tsx

@@ -9,11 +9,15 @@ import {
   Text,
 } from "@mantine/core";
 import type {
+  ProtocolEra,
   ReadResourceResult,
   Resource,
   ResourceTemplateType as ResourceTemplate,
 } from "@modelcontextprotocol/client";
-import type { InspectorResourceSubscription } from "../../../../../../core/mcp/types.js";
+import type {
+  InspectorResourceSubscription,
+  ResourceSubscriptionStreamState,
+} from "../../../../../../core/mcp/types.js";
 import { ResourceControls } from "../../groups/ResourceControls/ResourceControls";
 import type { ListPaginationControlsProps } from "../../elements/ListPaginationControls/ListPaginationControls";
 import { ResourcePreviewPanel } from "../../groups/ResourcePreviewPanel/ResourcePreviewPanel";
@@ -32,6 +36,14 @@ export interface ResourcesScreenProps {
   resources: Resource[];
   templates: ResourceTemplate[];
   subscriptions: InspectorResourceSubscription[];
+  /**
+   * Modern-era `subscriptions/listen` stream state (#1630). On the modern era
+   * the Subscriptions section shows a stream-status badge and a header dot;
+   * `active: false` (the legacy default) renders neither.
+   */
+  subscriptionStreamState?: ResourceSubscriptionStreamState;
+  /** Negotiated protocol era; gates the modern subscription stream chrome. */
+  protocolEra?: ProtocolEra;
   readState?: ReadResourceState;
   ui: ResourcesUiState;
   listChanged: boolean;
@@ -137,6 +149,8 @@ export function ResourcesScreen({
   resources,
   templates,
   subscriptions,
+  subscriptionStreamState,
+  protocolEra,
   readState,
   ui,
   listChanged,
@@ -291,6 +305,8 @@ export function ResourcesScreen({
             templates={templates}
             subscriptions={subscriptions}
             subscriptionsSupported={subscriptionsSupported}
+            subscriptionStreamState={subscriptionStreamState}
+            protocolEra={protocolEra}
             selectedUri={selectedResourceUri}
             selectedTemplateUri={selectedTemplateUri}
             searchText={search}