Put a template's indexed image first in Examples

[Robbie1977]

Part of VirtualFlyBrain/VFB2#500.

What changed: Examples records now carry index (from channel_image.image.index[0] when present), and each template's list is ordered by a new order_template_examples(): indexed images first, index ascending, then the rest by id descending as before.

Why: an image with an index is a domain in that template's label volume, so it belongs to the template and should lead Available Images. The index was in the vfb_json term_info but dropped here, so nothing downstream could use it.

How to test: python -m unittest test.test_examples_order from src/. Against live vfb_json, term_info_parse_object for FBbt_00003748 now gives JRC2018U VFB_00102107 (index 3) first, followed by the seven unindexed images newest first. Previously it came last.

Follow-ups: cached get_term_info entries keep the old order until they expire or are refreshed. Only order changes (plus an extra optional field), so I've not bumped the major.minor namespace. force_refresh on the neuropil classes that have more than one image on a template is enough. geppetto-vfb needs the matching carousel change (VirtualFlyBrain/geppetto-vfb#1744) or it re-sorts by id.

[github-actions]

⚠️ 165 test(s) skipped — an upstream data source was unreachable

The full suite ran, but 165 test(s) were skipped because an upstream data source (VFB's Neo4j / SOLR / Owlery, or FlyBase's Chado) did not answer during this run.

These are not failures and not a problem with this branch — but those queries went unverified, so a green check here is an incomplete run.

To re-run: open this workflow run and click Re-run all jobs once the data sources are healthy (re-running the “Run completeness” check itself does nothing — it has no job behind it).

686 passed, 165 skipped, 339 warnings in 582.06s (0:09:42)

_{Posted automatically. This comment is removed once a run completes with zero skips.}