[task-mode] Run the enrichment evals live #16

Follow-up to #6. Cases TASK-INIT-enrich-ready and TASK-INIT-enrich-readonly were added to evals/mcp-tool-use/cases/task-initialization.ndjson and build under --dry-run, but no paid API run was authorized. The ready path was exercised once live on Claude Haiku 5.5 in an isolated client; the read-only failure path (outcome failed) has not been run. Run both cases per evals/README.md when an API key is available.