Bugfix/download button

[KaiwenS7]

Fix to issue #4
Can be expanded to prevent any similar bugs from cropping up, but currently will work to deal with today's setup

[cpiker]

Looking at line 1754 it looks like it would be better if the surrounding python sent the URL stubs (obviously can't send the query params) to the client in advance when generating the js.

There will be one URL stub per download button. Even though many dasFlex setups typically only have one download source, technically there can be an arbitrary number of them for redundancy.

One concern I have is that the content-disposition's filename component is getting ignored somewhere in the form download. The data supplier (d3data.py) sets this using knowledge from the internal.json file on the server, so it's something we want to preserve since the sys-admin for the server has the ability to set filename patterns through that path.

For now I'd like to hold this request open for a more complete fix.

[KaiwenS7]

Takes the content-disposition now for the filename. Also fixes the issue originally brought forward

[cpiker]

Branch works fine in the test environment. Verified that both bugs are fixed.

Example filename before the fix:

• tr-tra_l1a_mag-hsk_flex-undefined_2025-08-19_2025-08-20.das

and after branch install:

• ts2_l1a_mag_hsk_2025-08-19.d3b

Thanks!