Add more arg types in Map transform

[juliohm]

Allow types in Map transform to enable convenient pipelines like

using TableTransforms
using Colors

ColorView(color=RGB; low=0.02, high=0.98) = LowHigh(; low, high) → Map(color)

[Copilot]

Pull Request Overview

This PR extends the Map transform to accept types in addition to functions, enabling more convenient pipeline patterns with type constructors. The changes allow passing types directly to the transform, which will be called as constructors on the selected columns.

• Extended Map constructor to accept types alongside functions as callable arguments
• Updated type definitions to support Union{Function,Type} instead of just Function
• Added comprehensive test coverage for the new type-based functionality

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/transforms/map.jl	Core implementation adding type support through updated type aliases and extraction logic
test/transforms/map.jl	Test cases covering type constructors with and without target names
test/shows.jl	Updated display tests to reflect new Union{Function, Type} signature

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.33%. Comparing base (ccd0a29) to head (72c7415).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #305   +/-   ##
=======================================
  Coverage   98.33%   98.33%           
=======================================
  Files          50       50           
  Lines        1440     1442    +2     
=======================================
+ Hits         1416     1418    +2     
  Misses         24       24           

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