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/mcp/remote/node/tokenAuthProvider.ts

@@ -1,5 +1,9 @@
 import type { OAuthClientProvider } from "@modelcontextprotocol/client";
-import type { OAuthClientInformation, OAuthClientMetadata, OAuthTokens } from "@modelcontextprotocol/client";
+import type {
+  OAuthClientInformation,
+  OAuthClientMetadata,
+  OAuthTokens,
+} from "@modelcontextprotocol/client";
 import type { RemoteAuthState } from "../types.js";
 
 const REMOTE_OAUTH_STUB_METADATA: OAuthClientMetadata = {

core/mcp/remote/remoteClientTransport.ts

@@ -3,8 +3,14 @@
  * Pure TypeScript; works in browser, Deno, or Node.
  */
 
-import type { Transport, TransportSendOptions } from "@modelcontextprotocol/client";
-import type { JSONRPCMessage, MessageExtraInfo } from "@modelcontextprotocol/client";
+import type {
+  Transport,
+  TransportSendOptions,
+} from "@modelcontextprotocol/client";
+import type {
+  JSONRPCMessage,
+  MessageExtraInfo,
+} from "@modelcontextprotocol/client";
 import type { InspectorServerSettings, StderrLogEntry } from "../types.js";
 import type { FetchRequestEntryBase } from "../types.js";
 import type {