need ability to securely and privately store user secrets and/or API keys

to let people query private data sets, we need some way to let users save API keys and other secrets to their user accounts, and allow them to inject those into data queries. For the injection bit we'll need to think through both the syntax, and the implementation WRT things like: where does the injection happen (client or server?) and can it happen securely without exposing secrets while still allowing people that don't hold the secret to view a report?

No file or test is identified. Start by locating the user-account and data-query entry points, then define the required secret-storage and query-injection behavior, including where injection occurs and how reports can be viewed without exposing secrets.

Written by the indexing model from the issue text.