audit indexing throughout the database

We probably have a ton of inefficient indexes, like #427

Here are some resources https://jon.chrt.dev/2026/04/15/things-you-didnt-know-about-indexes.html

https://use-the-index-luke.com/

No file, test, or entry point is named. Start by reviewing issue #427 and the repository’s relational-storage and index definitions, then use the linked indexing resources for context. Done should include a documented audit of inefficient indexes and clearly scoped follow-up changes.

Written by the indexing model from the issue text.