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/state/managedListState.ts

@@ -194,9 +194,10 @@ export abstract class ManagedListState<
    * concrete subclass event maps keep the call sites type-safe.
    */
   private emit(type: keyof M, detail: unknown): void {
-    (
-      this.dispatchTypedEvent as unknown as (t: keyof M, d: unknown) => void
-    )(type, detail);
+    (this.dispatchTypedEvent as unknown as (t: keyof M, d: unknown) => void)(
+      type,
+      detail,
+    );
   }
 
   private setListChanged(value: boolean): void {