Remove nonexistent compression scripts from gallery error guidance

## Problem

The current project-page gallery error messages instruct maintainers to run scripts that do not exist in either repository branch.

At `web@66efcf4f1f8a4aaf5cc937e5b6d5bd9724f3ea04`:

- `docs/static/js/test_set.js` says to run `bash compress_test_set.sh` and populate `TableVerse/test_set/`;
- `docs/static/js/compare.js` says to run `bash compress_compare.sh` and populate `TableVerse/compare/`;
- the complete `web` tree contains no `.sh` files;
- the deployed asset roots are `docs/test_set/` and `docs/compare/`.

Both messages have been unchanged since the initial web commit.

## Reproduction

1. Make either `test_set/list.json` or `compare/list.json` unavailable in a local Pages checkout.
2. Load the corresponding gallery.
3. Follow the recovery command shown in the error message.
4. Observe that the referenced script is absent and the stated output path does not match the deployed source tree.

## Expected behavior

A gallery load failure should identify the failed resource and direct maintainers to verify the checked-in JSON/media paths that the site actually consumes.

## Actual behavior

The page recommends commands and paths that cannot be used with the repository.

## Impact

The only recovery guidance shown during a gallery failure sends maintainers toward nonexistent tooling instead of the failed deployment input.

## Environment

- Pages source: `web@66efcf4f1f8a4aaf5cc937e5b6d5bd9724f3ea04`
- Live deployment verified byte-identical to the source
- `.sh` files in complete web tree: 0

Start with docs/static/js/test_set.js and docs/static/js/compare.js, then inspect the corresponding docs/test_set/ and docs/compare/ paths. Verify the gallery error messages identify the failed JSON or media resource and refer only to checked-in paths that the site consumes. Done means both recovery messages no longer mention nonexistent shell scripts or TableVerse output directories.

Written by the indexing model from the issue text.