Move repo, CI and the video worker over to the name Feuerwerk (#422)

Stage 3 of the rename. The repo now lives at meleki/feuerwerk, the
runners carry feuerwerk labels and the WSL distro on melektaus-atx is
called feuerwerk-ci. The code has to follow, or CI finds no runner and
the suite no longer picks the GPU path.

- ci.yml: workflow name feuerwerk, jobs on feuerwerk-ci (gate, stein2)
  and feuerwerk-wsl (suite, melektaus-atx).
- GAME_MAKER_* variables are now FEUERWERK_*. This includes
  FEUERWERK_BROWSER=wsl, which the runner config on melektaus-atx sets.
- The video worker runs as container feuerwerk-video with the image
  feuerwerk-video and works on /srv/feuerwerk.
- e2e.sh starts the unit feuerwerk-e2e, the CI image keeps its paths
  under the new name.
- README and repo links point to git.nockal.com/meleki/feuerwerk. The
  old URLs still redirect with 301.

Both runners keep their old labels until the first CI run with this
ci.yml is through. Then they go, together with the image tag
game-maker-ci:latest and GAME_MAKER_BROWSER in the atx config.

Tests:
- Gate on melektaus-atx through the renamed distro: CHECK EXIT 0,
  307 files, 4756 tests.
- e2e 60 on melektaus-atx: ALL PASSED, 20 checks. Renderer is the
  RTX 4070 through D3D12, so FEUERWERK_BROWSER reaches the GPU path.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/index.php

@@ -67,7 +67,7 @@ declare(strict_types=1);
  *   POST   ?r=videos&name=x.mov[&convert=0]  raw video bytes → {file,name,status,…}
  *   POST   ?r=videos/{file}/convert          → {file,name,status,…} | 403 | 404
  *   DELETE ?r=videos/{file}       → 204 | 403 | 404 | 409
- *                               (an upload is converted by the worker in `game-maker-video` (#402):
+ *                               (an upload is converted by the worker in `feuerwerk-video` (#402):
  *                                `status` is queued, converting with `progress`, failed with `error`,
  *                                or ready with width, height, duration, fps, audio and `poster`;
  *                                with `convert=0` it is only kept, `unconverted`, until it is asked

api/lib/VideoQueue.php

@@ -5,7 +5,7 @@ declare(strict_types=1);
  * The videos waiting to be converted (#402): `data/videos/queue/{folder}-{hash}.json` says what
  * became of an upload, and its `source` where the upload lies – kept as it came beside the MP4,
  * `{folder}/{hash}.source.{ext}`, for downloading it. The API adds to it, the worker in the
- * container `game-maker-video` takes from it, one at a time, oldest first.
+ * container `feuerwerk-video` takes from it, one at a time, oldest first.
  *
  * A job is `queued`, `converting` (with `progress` from 0 to 1) or `failed` (with `error`). A done
  * one is no job any more: its MP4 lies in the account's folder and the job is gone. A failed one

api/lib/VideoWorker.php

@@ -3,7 +3,7 @@ declare(strict_types=1);
 
 /**
  * Converts what waits in the VideoQueue, one video at a time (#402). Runs in the container
- * `game-maker-video` through `tools/video-worker.php`, and in CI beside the PHP server.
+ * `feuerwerk-video` through `tools/video-worker.php`, and in CI beside the PHP server.
  *
  * Each job goes: probe the upload, convert it into a temp file beside its target, read the result
  * back for its details, cut a poster, then move all three into place and drop the job. Whatever