fix(codeql): switch language matrix to 'actions' (no JS/TS in repo) (#30)

Same root cause as IJ.jl#6: CodeQL was pinned to `language: javascript-typescript` on a repo with no JS/TS source files, so the analyze job failed with a configuration error every run — blocking all Dependabot PRs.

Switches to `actions`, which scans the workflow files every repo has.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

Author: hyperpolymath