[codex] Add Etsy listings editor and clean up pages

[kevrez]

Summary

• add live Etsy listing list/detail/update routes and service methods
• replace the draft-only Streamlit page with Draft and Published listing tabs plus a side-pane editor
• rename the sidebar page from Etsy Draft Listings to Etsy Listings
• remove the Approval Queue, Design Queue, Product Drafts, and Analytics Streamlit pages
• add mock Etsy listing data and focused route/client tests

Root Cause / Context

Workshop only showed locally created draft records. It could not browse live Etsy published listings, and published inventory prices can arrive as Etsy money objects rather than plain numbers. The old sidebar also still exposed workflow pages that are no longer wanted.

Validation

• commit hook: ruff check .
• commit hook: ruff format --check .
• commit hook: mypy src
• pytest tests/unit/test_etsy_client.py tests/unit/test_etsy_listing_routes.py
• browser verified Published tab loads without the price TypeError