explorer: support searches of material samples described by a URI or PID identified concept

[ekansa]

It would be very handy for the explorer to select a set of material sample records that are described by concepts identified by a URI or PID.

For example, the URI https://vocab.getty.edu/aat/300263796 identifies a concept with the label “whorls (spindle flywheels)”. It would be good to get a selection material sample records described by keywords that include concept.

Another example would be the vocabulary concept https://w3id.org/isample/vocabulary/materialsampleobjecttype/organismpart (organism part). It would be good to get a selection of material samples records that have a sample object type for organism part, identified by that URI.

The Interactive Explorer should have a new URL parameter to be used for such queries (where the concept URI or PID is the value passed in the URL parameter). Perhaps described-by= can be used as a URL argument for the Interactive Explorer?

[rdhyee]

A1 (search-as-global-filter) just merged as #251 and is live on isamples.org, which gives this a clean foundation. A committed filter materializes a search_pids pid-set once, and every surface (samples table, globe points, facet counts, stats) constrains to it via a cheap semi-join. So #248 is essentially a new producer of that same pid-set.

Your two examples map to two flavors:

1. iSamples-vocabulary URIs (your organism-part example, https://w3id.org/isample/vocabulary/materialsampleobjecttype/organismpart) — these are exactly the URI-valued facet columns the explorer already carries (object_type / material / context). described-by=<uri> would build search_pids from an exact-URI match across those columns, and A1 then filters every surface automatically, with the concept's label resolved via the bundled vocab_labels. Starting on this one now.

2. Arbitrary external concept URIs (your Getty AAT "whorls" example, https://vocab.getty.edu/aat/300263796) — the sample records don't carry Getty URIs directly, so this likely resolves the concept URI → its label(s) and runs the free-text path on the label. That needs a URI→label resolution step beyond the bundled iSamples vocab_labels, so I'd propose treating it as a follow-on.

Will use described-by= as the URL parameter as you suggested, starting with flavor 1.