feat(verify): cross-reference smartphone records against Wikipedia

[Seungpyo1007]

Summary

Cross-reference tool to harvest verified Wikipedia URLs for unverified smartphone records (gsmarena-kaggle dataset).

• Reuses strict safeguards from crossref.py:
  • Exact heading matching (_heading_matches)
  • Requirement of >= 2 independent agreeing specifications (launch year alone is blocked)
  • Hard-gated variant confusion filters (Pro, Plus/+, Max, Ultra, Mini, Lite, Fold/Flip, 4G vs 5G, Tablet/Watch)
  • Rejection of multiple competing candidates (multiple-rows)
  • Brand isolation on WikiRow preventing cross-brand matching
• Supports fast sampling across brand directories without full filesystem scans
• Respects Wikipedia robot policy and rate limits
• Includes 11 comprehensive unit tests covering variant conflict, year-only block, spec rank, spec conflict, and HTML table extraction