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>

clients/web/src/components/groups/ToolControls/ToolControls.tsx

@@ -15,6 +15,8 @@ import type { Tool } from "@modelcontextprotocol/client";
 import type { ExcludedTool } from "@inspector/core/mcp/types.js";
 import { ListChangedIndicator } from "../../elements/ListChangedIndicator/ListChangedIndicator";
 import { ListLoadError } from "../../elements/ListLoadError/ListLoadError";
+import { MalformedItemsWarning } from "../../elements/MalformedItemsWarning/MalformedItemsWarning";
+import type { MalformedListItem } from "@inspector/core/mcp";
 import {
   ListPaginationControls,
   type ListPaginationControlsProps,
@@ -37,6 +39,12 @@ export interface ToolControlsProps {
    * A failed list load, surfaced above the list instead of leaving the panel
    * empty (which reads as "this server has none") (#1953).
    */
+  /**
+   * Entries the client dropped from this list because they failed the MCP
+   * schema. Rendered as a warning above the list, which still shows the rest
+   * (#1909).
+   */
+  malformedListItems?: MalformedListItem[];
   loadError?: Error | null;
   /** Pagination controls (#1721). */
   pagination: ListPaginationControlsProps;
@@ -127,6 +135,7 @@ export function ToolControls({
   searchText = "",
   listChanged,
   onRefreshList,
+  malformedListItems = [],
   loadError,
   pagination,
   onSearchChange,
@@ -163,6 +172,11 @@ export function ToolControls({
       />
       <ListPaginationControls {...pagination} />
       <ListLoadError error={loadError} what="tools" onRetry={onRefreshList} />
+      <MalformedItemsWarning
+        items={malformedListItems}
+        method="tools/list"
+        what="tools"
+      />
       <SidebarScroll viewportRef={viewportRef}>
         <Stack gap="xs">
           {filteredTools.map(({ tool, key }) => (