Decide whether to remove or implement inactive adapter scaffolds

[bdtran2002]

Summary

Make an explicit product and codebase decision about inactive marketplace adapter scaffolds.

Why

src/adapters/ebay.js and src/adapters/craigslist.js are not part of the active Facebook -> eBay runtime path, but they still exist in the repo and docs context.

Scope

• review whether these scaffolds are still part of the roadmap
• remove dead scaffolding if it is no longer planned
• or document the intended next steps if the adapters should remain
• align README and implementation docs with the decision

Acceptance criteria

• inactive adapters are either removed or intentionally documented
• docs no longer imply ambiguity about inactive scaffolds
• the active product path is clearer for future contributors