fix: remove sample DEM data from .Rbuildignore

[brownag]

• PR for patch release that will close [bug] file asset access issues on CRAN #135

[Copilot]

Pull Request Overview

This PR fixes an issue where sample DEM data was being excluded from the R package build by modifying the .Rbuildignore file to allow specific test data files while still excluding other TIFF files.

• Updated .Rbuildignore pattern to exclude TIFF files except for the specific DEM test data file
• Added defensive test code to handle cases where sample data files might not exist

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
.Rbuildignore	Modified regex pattern to allow inst/extdata/DEM.tif while excluding other TIFF files
tests/testthat/test-wbt_source.R	Added error handling and file existence checks for sample data

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[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

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