[SPARK-52428] Add Column comparison methods (gt, lt, ge, le)

[rafafrdz]

Closes #42

Summary

• Add Column::gt(other), lt(other), ge(other), le(other) comparison methods
• Uses same invoke_func pattern as existing eq, and, or
• Enables method chaining: col("age").gt(lit(27))

Test plan

• test_column_gt — verifies > function expression
• test_column_lt — verifies < function expression
• test_column_ge — verifies >= function expression
• test_column_le — verifies <= function expression
• cargo build passes
• cargo fmt -- --check passes