feat: add structured log for infinite scroll next page fetch

[fahatadam]

Summary

• Added a debug-level log to useInfiniteCreatorMarketplace that emits after each successful scroll-triggered next page fetch.
• The log explicitly includes cursor, results_fetched, has_more, and fetched_at fields.
• Guard clauses ensure the log is bypassed during the initial page load and in the test environment (import.meta.env.MODE === 'test').

Closes #624

Testing

• pnpm lint
• pnpm build

Checklist

• Linked issue or backlog item
• Scope is limited to the stated change
• Updated docs if behavior or setup changed
• Added screenshots for UI changes when relevant

[drips-wave]

@fahatadam Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

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