write-kaggle-benchmarks: autonomous setup, log before download, optional publish

[nicholaskang-us]

Three coupled changes to write-kaggle-benchmarks/SKILL.md:

1. Autonomous setup. Previously the skill checkpointed on every step,
   including read-only ones like init and auth, which made setup feel
   slow and chatty. New behavior: ask the user once up front to confirm,
   then run all of setup (pip upgrade kaggle + kaggle-benchmarks, verify
   auth, kaggle b init -y) without further prompts. Re-runs automatically
   on later auth/import errors — all steps are idempotent. Install + auth
   checks modeled on Kaggle/kaggle-cli skills/SKILL.md:
   https://github.com/Kaggle/kaggle-cli/blob/main/skills/SKILL.md

2. Log moves before Download. log is how you confirm a run actually
   succeeded, so it should come immediately after status and before
   download. Renumbered accordingly.

3. Publish is optional. Heading renamed to Publish (optional) and a
   lead-in clarifies that tasks can stay private indefinitely.

Pacing rule now only applies to authoring/execution steps that hit the
server: Write / Validate / Push / Run / Download. Read-only list,
status, and log run without confirmation.

[nl917]

LGTM! Thanks