Address @claude review: format core/, typed output-validation error, document progress heuristic

- Run Prettier on the 60 core/ files this PR touched — the deterministic
  import rewrite had collapsed multi-line imports and left throws unwrapped;
  core/ is in no format gate so it slipped past CI. Now Prettier-clean.
- Default-path output-schema violation now throws
  ProtocolError(ProtocolErrorCode.InvalidParams, …) instead of a bare Error,
  matching the prior v1 contract (SDK threw a typed McpError with a code) so
  downstream `instanceof`/`.code` branching keeps working.
- Document the "assumes serial construction" invariant on pollTaskToolCall's
  progress-subscription revival (the `_progressHandlers` new-key heuristic).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

core/react/usePagedTools.ts

@@ -21,9 +21,7 @@ export function usePagedTools(
   client: InspectorClientProtocol | null,
   pagedToolsState: PagedToolsState | null,
 ): UsePagedToolsResult {
-  const [tools, setTools] = useState<Tool[]>(
-    pagedToolsState?.getTools() ?? [],
-  );
+  const [tools, setTools] = useState<Tool[]>(pagedToolsState?.getTools() ?? []);
 
   useEffect(() => {
     if (!pagedToolsState) {