Improve Excel export formatting

[junnaid-4]

Summary

Improves the appearance and usability of XLSX lead exports.

Changes

• Added professional navy header styling
• Added striped Excel table formatting
• Added priority and website-status colors
• Added clickable website and Google Maps links
• Added content-aware bounded column widths
• Added number formats for ratings, counts, scores, and HTTP status
• Added wrapped text, borders, and top alignment
• Disabled gridlines
• Changed freeze panes to D2
• Hid technical columns while preserving their data
• Capped score_breakdown width
• Added controlled body-row heights
• Added landscape print settings and repeated header rows

Safety

• CSV behavior remains unchanged
• Exported columns and row ordering remain unchanged
• Atomic XLSX writing is preserved
• Spreadsheet formula-injection protection is preserved

Validation

• 150 tests passing
• Ruff checks passing
• Ruff formatting passing
• MyPy passing
• git diff --check passing