refactor: drop the ext-apps SDK-v1 shims now that 2.0.0 peers on SDK v2

Every site tagged `ext-apps#702` carried a workaround for ext-apps
peering on the v1 SDK while the Inspector runs v2. With 2.0.0 the
package's `AppBridge` extends the v2 `Protocol`, takes the v2 `Client`
and `Implementation` directly, and registers its list-changed forwarding
on that client with `setNotificationHandler("notifications/…", handler)`,
so:

- core/mcp/apps.ts: `getToolUiResourceUri(tool)` takes the v2 `Tool`
  without a cast; `UiMetaShape` is replaced by ext-apps' own
  `McpUiToolMeta` / `McpUiResourceMeta`, which resolve under NodeNext
  since ext-apps#705. `AppInfo.csp` / `.permissions` / `.visibility`
  take the named types too.
- core/mcp/inspectorClient.ts: `getAppRendererClient()` returns the SDK
  client itself; the Proxy that translated the 1.x schema-first
  `setNotificationHandler(Schema, handler)` into the method-string form,
  its `notificationMethodFromSchema` helper and its cached field are
  gone. `AppRendererClient` is now `Client` rather than `unknown`.
- createAppBridgeFactory.ts: `new AppBridge(client, HOST_INFO, …)` with
  no `as unknown as`; `resolveSourceUri` passes the tool straight through.
- AppRenderer.tsx: `sendToolResult(result)` — its params ARE the v2
  `CallToolResult` now.
- requestAppElicitation.ts: the double cast on the `elicitation/create`
  send goes too — v2 `Protocol.request` takes the standard `Request`
  shape, which `ElicitRequest` is. The helper itself stays: ext-apps#733
  is not in 2.0.0.
- core/mcp/extensions.ts: `MCP_APP_MIME_TYPE` re-exports ext-apps'
  `RESOURCE_MIME_TYPE` from `/app-bridge`; `UI_EXTENSION_KEY` stays
  hardcoded because `EXTENSION_ID` is still `/server`-only in 2.0.0.

Tests: the Proxy-translation test is removed with the Proxy; the
`getAppRendererClient` tests assert the real `Client` instance and that
disconnect withdraws it; the `useInspectorClient` sentinel is a real
(unconnected) `Client`. Comments that cited ext-apps 1.7.5 now cite 2.0.0
where the fact still holds (#733 still unreleased).

Closes #1745
Refs #2309

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PsmUAZ6aLUAFqenjJKSSRp
Signed-off-by: cliffhall <cliff@futurescale.com>

core/mcp/inspectorClient.ts

@@ -366,24 +366,6 @@ async function closeSubscriptionBestEffort(
   }
 }
 
-/**
- * Extract the method literal from an MCP notification Zod schema (e.g.
- * `ToolListChangedNotificationSchema`), or `undefined` if the shape isn't
- * recognized. Used by the App-renderer client proxy to translate the SDK-v1
- * schema-first `setNotificationHandler` API — which `@modelcontextprotocol/ext-apps`
- * still uses — into SDK v2's method-string form. Reads the `method` literal off
- * the notification schema's `shape` (the shape both the v1 SDK and v2 core
- * schemas expose).
- */
-function notificationMethodFromSchema(schema: unknown): string | undefined {
-  if (schema !== null && typeof schema === "object") {
-    const literal = (schema as { shape?: { method?: { value?: unknown } } })
-      .shape?.method?.value;
-    if (typeof literal === "string") return literal;
-  }
-  return undefined;
-}
-
 /**
  * The descriptor for a single tools/call, threaded through the retry loop and
  * each attempt. Bundled into one object so `callToolWithRetries`/`attemptToolCall`
@@ -488,7 +470,6 @@ export class InspectorClient extends InspectorClientEventTarget {
    */
   private static readonly MRTR_MAX_ROUNDS = 10;
   private client: Client | null = null;
-  private appRendererClientProxy: AppRendererClient | null = null;
   // Lazily-built validator used only on the skipOutputValidation path to detect
   // (non-fatally) when a delivered result violates the tool's outputSchema.
   private outputValidator: AjvJsonSchemaValidator | null = null;
@@ -1017,7 +998,6 @@ export class InspectorClient extends InspectorClientEventTarget {
     this.rootsListChangedCapabilityAdvertised =
       capabilities.roots?.listChanged === true;
 
-    this.appRendererClientProxy = null;
     this.clientInfo = options.clientIdentity ?? {
       name: corePackageJson.name.split("/")[1] ?? corePackageJson.name,
       version: corePackageJson.version,
@@ -2612,7 +2592,6 @@ export class InspectorClient extends InspectorClientEventTarget {
     this.activeToolCallAbortController?.abort("Disconnected");
     this.activeToolCallAbortController = undefined;
     this.clearReceiverTasks();
-    this.appRendererClientProxy = null;
     this.capabilities = undefined;
     this.serverInfo = undefined;
     this.instructions = undefined;
@@ -2644,44 +2623,19 @@ export class InspectorClient extends InspectorClientEventTarget {
   }
 
   /**
-   * Returns a client proxy for use by AppRenderer / @mcp-ui. Delegates to the
-   * internal MCP Client. Returns null when not connected. Use this instead of
-   * accessing the raw client so behavior can be adapted here later if needed.
+   * The SDK client for the MCP Apps host bridge, or null when not connected.
+   *
+   * ext-apps' `AppBridge` (2.0.0+, an SDK v2 peer) takes the v2 `Client`
+   * directly and registers its list-changed forwarding on it in the
+   * method-string form, so this hands out the real client. The Proxy that
+   * translated the 1.x peer's schema-first `setNotificationHandler(Schema,
+   * handler)` into that form is gone with it (#1745). Kept as the seam rather
+   * than exposing the field so the connected-status gate lives in one place
+   * and hooks, fakes and tests depend on the protocol, not the class.
    */
   getAppRendererClient(): AppRendererClient | null {
     if (!this.client || this.status !== "connected") return null;
-    if (this.appRendererClientProxy !== null)
-      return this.appRendererClientProxy;
-    const target = this.client;
-    this.appRendererClientProxy = new Proxy(this.client, {
-      get(proxyTarget, prop, receiver) {
-        const value = Reflect.get(proxyTarget, prop, receiver);
-        if (prop === "setNotificationHandler" && typeof value === "function") {
-          return (schemaOrMethod: unknown, ...rest: unknown[]) => {
-            // `@modelcontextprotocol/ext-apps` still peers on SDK v1 and
-            // subscribes to list-changed notifications with the v1 schema-first
-            // API `setNotificationHandler(NotificationSchema, handler)`. SDK v2
-            // requires a method STRING as the first argument and throws
-            // "'[object Object]' is not a spec notification method" on a schema —
-            // which broke App rendering during the initial connect handshake.
-            // Translate a schema-first call to the method-string form; native
-            // string-first calls (ours) pass through untouched. Remove when
-            // ext-apps#702 ships a v2 peer.
-            const method =
-              typeof schemaOrMethod === "string"
-                ? schemaOrMethod
-                : (notificationMethodFromSchema(schemaOrMethod) ??
-                  schemaOrMethod);
-            return (value as (...a: unknown[]) => unknown).apply(target, [
-              method,
-              ...rest,
-            ]);
-          };
-        }
-        return value;
-      },
-    }) as AppRendererClient;
-    return this.appRendererClientProxy;
+    return this.client;
   }
 
   /**