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>

tools/ci/Dockerfile

@@ -1,7 +1,7 @@
-# The image behind the Gitea Actions label `game-maker-ci`. It is built on the host and kept
+# The image behind the Gitea Actions label `feuerwerk-ci`. It is built on the host and kept
 # local (the runner has `force_pull: false`), so a change here needs a rebuild:
 #
-#   DOCKER_BUILDKIT=0 docker build --network git_default -t game-maker-ci:latest tools/ci
+#   DOCKER_BUILDKIT=0 docker build --network git_default -t feuerwerk-ci:latest tools/ci
 #
 # Both flags are needed on stein2: DNS is dead in Docker's default bridge network, and Buildkit
 # cannot join a named network.
@@ -10,11 +10,11 @@ FROM node:22-bookworm
 # chromium + the Vulkan drivers: the e2e harness starts chromium with --use-angle=vulkan and has
 # no software fallback. The render device itself comes from the runner's container.options;
 # without it chromium falls back to llvmpipe and gets WebGL 1.0 only.
-# xvfb serves the other GPU path, GAME_MAKER_BROWSER=wsl (tools/lib/browser.mjs): under WSL2 the
+# xvfb serves the other GPU path, FEUERWERK_BROWSER=wsl (tools/lib/browser.mjs): under WSL2 the
 # GPU is /dev/dxg behind Mesa's d3d12 driver, which headless chromium cannot reach, an X11 one can.
 # php-cli serves api/index.php, which every tool loads and saves its project through.
 # ffmpeg converts uploaded videos (#402), through tools/video-worker.php like the container
-# game-maker-video on stein2 does.
+# feuerwerk-video on stein2 does.
 # The fonts are the host's set on purpose: the checks measure text widths to find click points,
 # so a different set moves them.
 RUN apt-get update && apt-get install -y --no-install-recommends \