Plugins are switched on and off in a Plugins tab, the server keeps the state in data/plugins/plugins.json, and switched-off plugins are never delivered (#114)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tools/seed-e2e.mjs

@@ -6,24 +6,22 @@
  *
  * Usage: node tools/seed-e2e.mjs [projectId] [baseUrl]
  */
-import { copyFileSync, mkdirSync, readdirSync } from 'node:fs';
 import { fileURLToPath } from 'node:url';
 import { sineWav } from './lib/audio.mjs';
 import { edge, node, port, sceneObject, variable } from './lib/builders.mjs';
+import { publishPlugins } from './lib/plugins.mjs';
 import { PROJECTS, cliArgs, uploadFont, uploadSound, writeProject } from './lib/projects.mjs';
 import { adjustColorsShader } from './lib/shaders.mjs';
 
 const { projectId, baseUrl } = cliArgs('seed-e2e.mjs', PROJECTS.fixture);
 
 /**
- * The plugins that ship with the repository, where the editor loads them from – the build does the
- * same, this makes a run after a plain checkout independent of it. The server is this checkout
+ * The plugins that ship with the repository, where the editor loads them from and switched on –
+ * the build does the same, this makes a run after a plain checkout independent of it, and puts the
+ * demo plugin back on after a step (or a person) switched it off. The server is this checkout
  * (locally and in CI), so a file copy is enough.
  */
-const ROOT = fileURLToPath(new URL('..', import.meta.url));
-mkdirSync(`${ROOT}data/plugins`, { recursive: true });
-for (const file of readdirSync(`${ROOT}plugins`).filter((f) => f.endsWith('.js')))
-  copyFileSync(`${ROOT}plugins/${file}`, `${ROOT}data/plugins/${file}`);
+publishPlugins(fileURLToPath(new URL('..', import.meta.url)), { force: true });
 
 /**
  * Two typefaces for the font step to pick and to drop. They are put on the server but not made