Unable to run custom queries against GitHub Actions

Start by comparing the standalone CodeQL commands with the GitHub Actions invocation and the generated codescanning configuration. Inspect actions-queries/pull_request_target.ql and the workflow shown in the linked pull request, then rerun the workflow after identifying why no Actions queries are defined. Done means the custom query runs through Actions without the fatal error.

I've been trying to use codeql to check my GitHub Actions workflows. I've got it kinda working here:

https://github.com/billnapier/github-actions-check-workflow/pulls

I can test things, and when I run codeql standalone, stuff works just fine:

codeql database create --force-overwrite --db-cluster /workspaces/c 
--source-root=/workspaces/github-actions-check-workflow --calculate-language-specific-baseline --extractor-include-aliases --sublanguage-file-
coverage --language=actions --search-path /workspaces/codeql-action --build-mode=none

and then run the query:

codeql query run --database /workspaces/c/actions -- actions-queries/pull_request_target.ql

So my query is well formed, and I can generate the DB. But when I try and run it via Actions, I get this output instead (also in the PR):

Encountered a fatal error while running "/opt/hostedtoolcache/CodeQL/2.20.3/x64/codeql/codeql database init --force-overwrite --db-cluster /home/runner/work/_temp/codeql_databases --source-root=/home/runner/work/github-actions-check-workflow/github-actions-check-workflow --calculate-language-specific-baseline --extractor-include-aliases --sublanguage-file-coverage --language=actions --search-path /home/runner/work/_actions/github/codeql-action/v3/actions-extractor --codescanning-config=/home/runner/work/_temp/user-config.yaml --build-mode=none". Exit code was 2 and error was: A fatal error occurred: No queries defined for actions. See the logs for more details.

I've been trying to debug the "No queries defined for actions", but I'm stumped. I'm guessing that I'm missing something specifying what language my query is used for, but I have no idea what I'm missing.