Rename Game Maker to Feuerwerk and serve it at /feuerwerk/ (#422)

The editor gets a name of its own that fits beside Brandmauer,
Glutspeicher and Feuerwehr. This is stage 1, 2 and 4 of #422: the
name, the URL and the stored state in the browser. Repository, CI
runners, containers and the GAME_MAKER_* variables follow in stage 3.

- All paths come from SITE_PATH in src/core/site.ts: the API endpoint,
  the data folders, the play page and the base in vite.config.ts. A
  later move is one line instead of fifteen.
- The window title, the sign-in screen, the playground and the README
  say Feuerwerk. The package, __feuerwerkPlay, the take worklet and the
  writing app in Ogg and Matroska follow.
- The session cookie is now feuerwerk_session, so everyone signs in
  once more.
- localStorage keys are now feuerwerk.*. moveOldStoredKeys copies the
  old game-maker.* keys over on the first start, so settings, panel
  sizes and save games survive.
- tools/ci/serve.sh serves the build under /feuerwerk/. The variable
  GAME_MAKER_BASE_URL keeps its name until stage 3.

Outside the repository, nockal.com/feuerwerk/ is a second symlink to
the same tree. nginx sends the bare /game-maker/ folder there with a
301. Everything else under /game-maker/ is still served directly, so
shared play links and the API keep working.

Finding: when nginx redirects a path without a trailing slash or with
a query, the Brandmauer answers with its own 307 to the same URL plus
a slash, placed after the query. A play link would lose its token that
way, which is why only the bare folder is redirected.

Tests:
- Gate on melektaus-atx: CHECK EXIT 0, 307 files, 4756 tests
  (4 new in site.test.ts).
- Counter-check: when the migration misses the old prefix, 3 of the
  4 new tests fail.
- e2e 60 under /feuerwerk/: ALL PASSED, 20 checks.
- From outside: /feuerwerk/ 200, /game-maker/ 301, an old play
  link 200.

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

src/editor/App.ts

@@ -21,10 +21,9 @@ import { Editor } from './Editor';
 import { isDragFrame } from './framePreview';
 import { startPlugins } from './plugins/startPlugins';
 import { CelUploadStore } from './pixelart/celUploadStore';
+import { API_ENDPOINT } from '../core/site';
 import { EditorState } from './state';
 
-const API_ENDPOINT = '/game-maker/api/index.php';
-
 /**
  * Shows the sign-in screen until somebody is signed in, and answers with their name. Returns
  * right away when the session from an earlier visit is still good – which is what lets a
@@ -70,7 +69,7 @@ export async function startEditor(app: Application, root: VStack): Promise<void>
     const { user, role } = await signedInUser(app, root, auth);
     // Who is signed in goes into the window title: the toolbar is crowded enough, and the title is
     // also what tells two tabs on two accounts apart.
-    document.title = `Game Maker – ${user}`;
+    document.title = `Feuerwerk – ${user}`;
     const state = new EditorState();
     // Drawn pictures (#185) are looked up in the project this session holds; the next session
     // installs its own, which is also what lets go of everything the old one had drawn.
@@ -123,7 +122,7 @@ export async function startEditor(app: Application, root: VStack): Promise<void>
    */
   const endSession = async (editor: Editor): Promise<void> => {
     await editor.dispose();
-    document.title = 'Game Maker';
+    document.title = 'Feuerwerk';
     // The console panel is page-wide, the lines in it are not: what one account's project printed
     // is none of the next one's business.
     consoleLog.clear();

src/editor/auth/LoginScreen.ts

@@ -46,7 +46,7 @@ export class LoginScreen extends VStack {
     this.add(new Spacer(), 1);
 
     const card = new Card();
-    card.add(new Label('Game Maker', { style: 'title' }));
+    card.add(new Label('Feuerwerk', { style: 'title' }));
     card.add(new Label('Sign in to open your projects', { style: 'muted' }));
     card.add(new Spacer(Theme.gap));
 

src/editor/editorRecordingSettings.ts

@@ -5,7 +5,7 @@
  */
 import { editorRecordingSettingsOf, type EditorRecordingSettings } from '../core/recording/editorRecording';
 
-const STORAGE_KEY = 'game-maker.editor-recording';
+const STORAGE_KEY = 'feuerwerk.editor-recording';
 
 let kept: EditorRecordingSettings | null = null;
 

src/editor/generalSettings.ts

@@ -5,7 +5,7 @@
  */
 import { clamp } from '../ui/math';
 
-const STORAGE_KEY = 'game-maker.general-settings';
+const STORAGE_KEY = 'feuerwerk.general-settings';
 
 export interface GeneralSettings {
   /** How long a zoom takes to reach its new step, in ms; 0 jumps at once. */

src/editor/panelSizes.ts

@@ -5,7 +5,7 @@
  */
 import { clamp } from '../ui/math';
 
-const STORAGE_KEY = 'game-maker.panel-sizes';
+const STORAGE_KEY = 'feuerwerk.panel-sizes';
 
 let sizes: Map<string, number> | null = null;
 

src/editor/saves.ts

@@ -24,7 +24,7 @@ function browserStore(): Store | null {
 }
 
 export function saveKey(projectId: string, area: SaveAreaName): string {
-  return `game-maker.saves.${projectId}.${area}`;
+  return `feuerwerk.saves.${projectId}.${area}`;
 }
 
 function readArea(store: Store | null, key: string): SavedValues {

src/editor/sectionFolds.ts

@@ -5,7 +5,7 @@
  */
 import { Theme } from '../ui/Theme';
 
-const STORAGE_KEY = 'game-maker.folded-sections';
+const STORAGE_KEY = 'feuerwerk.folded-sections';
 
 let folded: Set<string> | null = null;
 

src/editor/song/SongEditor.ts

@@ -53,7 +53,7 @@ const INFO_WIDTH = 200;
 const GRID_WIDTH = 64;
 const INPUT_WIDTH = 104;
 /** Where the browser keeps the input picked last. */
-const INPUT_KEY = 'game-maker.record-input';
+const INPUT_KEY = 'feuerwerk.record-input';
 
 /** What the tab shows below its header: the tracks along time, or where they go (#350). */
 export type SongView = 'timeline' | 'routing';

src/editor/video/VideoCanvas.ts

@@ -40,7 +40,7 @@ import {
   zoomWave,
 } from '../sound/waveView';
 import { soundLibrary } from '../../viewport/SoundLibrary';
-import { openVideo } from '../../viewport/VideoLibrary';
+import { openVideo, videoFileUrl } from '../../viewport/VideoLibrary';
 import { chaseSeeks, seekChase, type SeekChase, seekVideo } from '../../viewport/videoSeek';
 import type { EditorState } from '../state';
 import { containRect } from '../texture/imageGrid';
@@ -376,7 +376,7 @@ export class VideoCanvas extends Widget {
       chase: seekChase(),
       asked: held,
       gain: null,
-      element: openVideo(`/game-maker/data/videos/${asset.file}`, held, (texture) => {
+      element: openVideo(videoFileUrl(asset.file), held, (texture) => {
         if (this.preview !== preview) return texture.destroy(true);
         preview.texture = texture;
         texture.source.on('update', () => this.invalidate());