Fix CI: commit pnpm-lock.yaml + install ffmpeg/imagemagick in test workflow

The sh1pt test workflow uses `cache: pnpm` + `pnpm install
--frozen-lockfile`, which require a committed lockfile, but .gitignore
excluded pnpm-lock.yaml — so the job failed with "Dependencies lock
file is not found". The test suite also shells out to ffmpeg/ffprobe and
ImageMagick, which aren't on the runner.

- Stop gitignoring pnpm-lock.yaml and commit it (pnpm 10.6.5)
- Add an apt install step for ffmpeg + imagemagick to test.yml

Verified locally: 85 passing, 12 pending, 0 failing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ralyodio

.github/workflows/test.yml

@@ -19,6 +19,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # The test suite shells out to ffmpeg/ffprobe and ImageMagick's convert;
+      # install them so the integration tests can run on the runner.
+      - name: Install FFmpeg and ImageMagick
+        run: sudo apt-get update && sudo apt-get install -y ffmpeg imagemagick
+
       # pnpm version is read from the "packageManager" field in package.json.
       # Do not pin a version here — it conflicts with packageManager and fails
       # with ERR_PNPM_BAD_PM_VERSION.

.gitignore

@@ -8,7 +8,6 @@ yarn-debug.log*
 yarn-error.log*
 .pnpm-debug.log*
 
-pnpm-lock.yaml
 ffmpeg_build/
 
 # Environment variables