fix(cli): mirror errorClass onto ErrorClassification (CDK↔CLI type sync)

#599 added `errorClass?: ErrorClassType` to the CDK ErrorClassification, which
serializes into the GET /tasks/{id} `error_classification` response — but the
hand-maintained CLI mirror (cli/src/types.ts) wasn't updated, so the CLI's
structured error display couldn't surface the transient/service/user axis (real
drift per the CLAUDE.md shared-API-shape routing rule).

Add the optional field to the CLI's ErrorClassification, inlined as a union
literal rather than a named `ErrorClassType` export — the types-sync drift check
(scripts/check-types-sync.ts) requires CDK to be the source of truth for any
exported type name, and CDK exports ErrorClassType from error-classifier.ts, not
shared/types.ts. Inlining keeps the field synced without a CLI-only export.

Verified: `//:check:types-sync` OK (57 CLI exports validated), cli build green
(600 tests, compile + eslint clean).

Author: isadeks

cli/src/types.ts

@@ -75,6 +75,11 @@ export interface ErrorClassification {
   readonly description: string;
   readonly remedy: string;
   readonly retryable: boolean;
+  /** Retry-semantics axis: transient (self-heals on retry) vs service (admin
+   *  must fix) vs user (change the request/code). Optional (older classifications
+   *  omit it; absent ⇒ user). Inlined (not a named export) to mirror the cdk
+   *  ErrorClassification field without introducing a CLI-only exported type. */
+  readonly errorClass?: 'transient' | 'service' | 'user';
 }
 
 /** Task detail returned by GET /v1/tasks/{task_id}. */