fix: surface list-fetch failures instead of swallowing them

A list load that failed — a transport error, or a result the SDK's era
codec rejects as invalid — reported nothing. The connect-time refresh is
fired with no caller to await it (`void this.refresh()`), so its rejection
became an unhandled rejection: the header said "Connected", the panel
rendered an empty list indistinguishable from a server that has none, and
the failed exchange showed in the Protocol panel as a clean success.

Two surfaces now tell the truth:

- ManagedListState records the failure as observable state (`getError` +
  an `errorChange` event) and still re-throws, so App's auth-recovery
  wrapper keeps working. The four `useManaged*` hooks expose it via a
  shared `useManagedListError`, and the Tools/Prompts/Resources sidebars
  render a `ListLoadError` alert with the reason and a Retry.
- A response the client refused is attributed back to its Protocol entry
  (`markResponseRejected` → `responseRejected` → `MessageEntry.clientError`),
  which now renders an Error status and a "Rejected by the Inspector"
  alert rather than the green resultType badge alone. The SDK gives no
  request id with a decode failure, so the id is recovered by correlation;
  see the comment on `markResponseRejected` for why that is exact.

Also stops `listAllTools` from dropping a failing excluded-tools walk on
the floor — it stays non-fatal but is logged.

Closes #1953

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SW1p8E2uiyyLx4RKwrwSrt

core/mcp/inspectorClientProtocol.ts

@@ -105,6 +105,15 @@ export interface InspectorClientProtocol extends InspectorClientEventTarget {
    * and the modern task store's poll-based refresh. */
   isTasksExtensionNegotiated(): boolean;
 
+  /**
+   * Mark the response that most recently answered `method` as rejected by the
+   * client, so its Protocol entry shows the reason instead of rendering as a
+   * clean success (#1953). Optional so existing test doubles satisfy the
+   * interface without implementing it; see `InspectorClient` for how the id is
+   * correlated and why that correlation is exact.
+   */
+  markResponseRejected?(method: string, reason: string): void;
+
   // Aggregate (all-page) list methods used by the managed state stores on
   // refresh. Unlike the single-page methods above, these route through the
   // SDK's cache-aware high-level verbs so `cacheMode` ('use' | 'refresh' |