feat(target): add read-only MCP server

[walkerhughes]

Summary

• add a read-only Target MCP server for store-scoped search and TCIN detail
• expose product-aware nearby store and pickup signals
• price draft shopping lists with alternatives and incomplete-price accounting
• include Claude Code and Codex manifests plus a Target shopping and menu-planning skill
• fail explicitly when Redsky presents an automated-traffic challenge

Safety and data boundaries

• no cart, account, order, or checkout writes
• all price claims retain their selected Target store context
• pickup status is identified as a point-in-time website signal, not a reservation

Validation

• make check
• make coverage (89.22%)
• official plugin validator
• official skill validator