feat(review): skill-bearing workers get no injected default task

Product intent: entire invokes the configured skills in parallel across agents — it does not add prompts of its own unless the user configured them. Previously an empty profile task was silently filled with the built-in comprehensive-audit brief (correctness, regressions, API design, missing tests, maintainability...), and any non-empty Task also dragged in the output-format protocol. A worker configured with only "skills" therefore received a maximal-audit mandate the user never wrote — measured live as the difference between a ~14-minute entire-spawned review and the same skill invoked directly by the user.

Per-worker task resolution: a user-configured task always reaches every worker verbatim; with no user task, skill-bearing workers get an empty Task (skills define behavior — and no Task means no injected output protocol either), while skill-less workers keep the built-in default as fallback so their prompt isn't empty. The judge still receives the canonical profile task for consolidation.