feat(cli): Add filter/query command

[arcaputo3]

Summary

Add commands to filter data ranges or query spreadsheet data.

Syntax

# Simple filter view (doesn't modify file, just displays)
xl -f file.xlsx -s Sheet1 filter A1:F100 --where "B > 100"
xl -f file.xlsx -s Sheet1 filter A1:F100 --where "A LIKE 'Widget%'"

# SQL-like query
xl -f file.xlsx query "SELECT A, B, SUM(C) FROM Sheet1 WHERE B > 100 GROUP BY A"

Filter Expressions

• B > 100 - Numeric comparison
• A = "Widget" - Exact match
• A LIKE "Widget%" - Wildcard match
• A IN ("A", "B", "C") - Set membership
• B BETWEEN 10 AND 100 - Range

Query Language (Ambitious)

Mini SQL dialect:

• SELECT columns
• FROM sheet
• WHERE conditions
• GROUP BY columns
• ORDER BY columns
• LIMIT n

Implementation Notes

This is a complex feature. Consider:

1. Simple filter expressions first
2. Full query language as separate milestone
3. Output to stdout (view mode) vs new sheet

Acceptance Criteria

• Basic --where filter works
• Wildcard matching works
• Output displays filtered rows
• (Optional) SQL-like queries

Priority

Low - Advanced feature

Milestone

v0.8.0+