fix: salvage a list result's valid entries when one is malformed (#1909)

The SDK validates a list result as a whole, so a single non-conforming entry
rejected the entire response and the panel showed "Couldn't load resources"
with zero items — the exact opposite of what a debugging tool should do with a
server that is 90% right. Reported against a PHP server whose empty
`annotations` object reaches the wire as `[]` rather than `{}`.

`listAll*` now falls back to a lenient re-walk when — and only when — the SDK
rejects a result it received (`InvalidResult` / `UnsupportedResultType`), keeps
the entries that validate, and reports the rest. A conforming server takes the
strict, cache-aware path exactly as before.

Salvaging is not accepting: the dropped entries are named with their reason in
a warning above the list, and the Protocol entry is still marked rejected, so
the wire truth survives. When every entry validates, the original error is
rethrown rather than swallowed — the rejection was about something the
per-item pass cannot explain.

`isClientDecodeRejection` moves to the new module and is now shared with
managedListState, which had the only copy.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
Signed-off-by: cliffhall <cliff@futurescale.com>

core/mcp/inspectorClientEventTarget.ts

@@ -26,6 +26,7 @@ import type {
   ResourceSubscriptionStreamState,
   ExcludedTool,
 } from "./types.js";
+import type { MalformedListItem } from "./listSalvage.js";
 import type {
   Tool,
   ServerCapabilities,
@@ -62,6 +63,12 @@ export interface InspectorClientEventMap {
    * connections (which don't exclude) and before connect (#1632).
    */
   excludedToolsChange: ExcludedTool[];
+  /**
+   * Entries dropped from a list result because they failed the spec schema for
+   * their primitive, across every list method. Empty against a conforming
+   * server; a non-empty set means the list rendered without them (#1909).
+   */
+  malformedListItemsChange: MalformedListItem[];
   capabilitiesChange: ServerCapabilities | undefined;
   serverInfoChange: Implementation | undefined;
   instructionsChange: string | undefined;