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/screens/ToolsScreen/ToolsScreen.tsx

@@ -1,4 +1,5 @@
 import { Card, Flex, Stack, Text } from "@mantine/core";
+import type { MalformedListItem } from "@inspector/core/mcp";
 import type {
   CallToolResult,
   ReadResourceResult,
@@ -50,6 +51,11 @@ export interface ToolsScreenProps {
   /** Tools the SDK excluded from `tools/list` for invalid `x-mcp-header`
    * annotations (SEP-2243), shown in the sidebar with the reason (#1632). */
   excludedTools?: ExcludedTool[];
+  /**
+   * Entries dropped from a list result as malformed, across every list method.
+   * Each list panel filters for its own and warns about them (#1909).
+   */
+  malformedListItems?: MalformedListItem[];
   callState?: ToolCallState;
   ui: ToolsUiState;
   listChanged: boolean;
@@ -147,6 +153,7 @@ const EmptyState = Text.withProps({
 export function ToolsScreen({
   tools,
   excludedTools,
+  malformedListItems,
   callState,
   ui,
   listChanged,
@@ -191,6 +198,7 @@ export function ToolsScreen({
           <ToolControls
             tools={tools}
             excludedTools={excludedTools}
+            malformedListItems={malformedListItems}
             selectedName={selectedToolName}
             searchText={search}
             listChanged={listChanged}