[FEAT] Imviz: Show the name of the dataset being used for the cursor readback (currently in Compass)

[hcferguson]

Description

Show the name of the dataset that is currently being used for the cursor readback (pixel coords & flux in the upper right).

Additional context

The cursor read back doesn't tell you which image it applies to. Nor does the Imviz viewer tell you which image is "on top" in the stack.

[pllim]

It does but in Compass plugin. There is no space in the "cursor readback" area.

See https://jdaviz.readthedocs.io/en/latest/imviz/plugins.html#compass

[kecnry]

There was an idea floated around to indicate the "top layer" in the data dropdown menu, which would at least expose this in a more "global" place than a seemingly-unrelated plugin. We could also consider this when we add labels on the viewers themselves (e.g., "Imviz-0: top-layer-data-label").

[pllim]

Imviz-0: top-layer-data-label

JWST label might be very long, then we have a problem with overcrowding of viewer tabs when multiple viewers are open. 🤷

[hcferguson]

Another possibility might be to let the user toggle between sexagesimal or decimal in a plugin window, rather than showing both, and then use the real-estate thus saved to show the name of the dataset (truncated if necessary).

[pllim]

let the user toggle between sexagesimal or decimal in a plugin window, rather than showing both

@PatrickOgle wanted both shown, so he should comment.