- 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>