Add top-sellers-in-category skill

[norightsforlis]

Summary

Adds the top-sellers-in-category skill: Ranks the top sellers in a category by estimated average revenue — a single point-in-time leaderboard with full seller stats.

Lives in skills/top-sellers-in-category/SKILL.md and is registered in the README skills table. Public behavior and user-visible workflow only — no internal service names, schema, or implementation details.

Public-Safety Checklist

• No credentials, tokens, keys, or secrets.
• No internal filesystem paths.
• No private Slack, Jira, Notion, admin, or service URLs.
• No private service names or implementation details.
• No customer data or private product data.
• Skill directory name matches SKILL.md frontmatter name.

🤖 Generated with Claude Code

[profunctor]

KISS review: this skill references category-top-100 change tracker, seller-overview tracker, and brand-position tracker, but those skills are not present in this PR’s target branch.

That can make agents route users to unavailable workflows. Please remove these handoff promises or replace them with generic wording until those skills exist in the catalog.

[profunctor]

Review — top-sellers-in-category

Summary: Read-only skill that, given a free-text category, uses JoomPulse to rank a Mercado Livre (Brasil) category's sellers by estimated average revenue and returns a point-in-time leaderboard (avg sales/revenue, last-365-day sales, cancellation rate, trend, brands, product distribution, international shipping, listing-type counts), with per-seller links and an optional cards + medal-colored bar chart.

Findings:

• minor — Description/body reference sibling skills that don't exist yet ("category-top-100 change tracker", "seller-overview tracker", "brand-position tracker"). Drop them or gate as "if available" until those PRs land, and use canonical slugs.
• minor — "average revenue" vs "average monthly revenue" inconsistency. Frontmatter/README/intro say "average revenue"; Step 2 and the cards say "average monthly revenue"/"average ticket". The table header Receita méd. is also ambiguous on period. Pin the period and name it once.
• nit — Prerequisites claim JoomPulse returns "medal, reputation" per seller and the chart colors by a medal field, but neither appears in the output table. Tighten the "when available" wording.
• nit — Folder name matches name; no secrets, internal paths, or hardcoded IDs; read-only. Public-safety checklist holds.

No blockers. The dangling references and the revenue-period inconsistency are the two worth fixing before merge.