Plugins belong to the project, and they load before it: the project file gained the field plugins: ["demo-plugin.js"] (default empty, no formatVersion bump), the Plugins tab's switch writes into it as an ordinary undo step (SetPluginActiveCommand) instead of into a server-wide plugins.json, and the start order is turned around - startPlugins only fetches the list of files, then editor.boot() runs and ProjectStore.load(id, prepare) hands the raw JSON through before it is deserialized, where pluginsOf(raw) reads the list and PluginManager.syncTo() activates exactly those; that is the point of the issue, because what a plugin registers has to stand there before normalizeGraph would throw it away as unknown (#126, #127), a project switch first stops what the new project does not name and then starts what it does, a file the server does not have is passed over silently, and after signing out the manager is dead so a late event cannot start anything in a torn-down session; on the server plugins.json, PluginStore::setActive, isActive, the route PUT ?r=plugins/{file} and the 403 for inactive modules are gone and GET ?r=plugins only answers {file,bytes,updatedAt}, which makes every plugin file fetchable - the consequence accepted in #117, written down in the wiki for #115 and #116; publishPlugins(root) only copies files now, the seeder switches the demo plugin on in the fixture project, and the Plugins tab carries a puzzle piece as its icon while only a plugin's own tab still goes without one (the knob and the socket are cubic curves, not arcs, which Pixi's parser draws as a spike after an L); 3 new e2e checks in module 38 and 5 new unit tests cover the project as the owner of the switch, its undo, the order, pluginsOf against crude input and an unknown file name (#119)

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

src/editor/plugins/PluginsPane.ts

@@ -57,9 +57,9 @@ class PluginRow extends HStack {
 }
 
 /**
- * The Plugins tab (#114): every file in `data/plugins/` with a switch. Switching one on loads and
- * activates it there and then, switching it off takes its tabs and listeners away again – the
- * state is the server's, so it holds for everyone who opens this editor.
+ * The Plugins tab (#114, #119): every file in `data/plugins/` with a switch. Switching one on loads
+ * and activates it there and then, switching it off takes its tabs and listeners away again – the
+ * switch is part of the open project, so it travels with it and undo takes it back.
  *
  * A plugin that is off is never loaded, which is why its row has no name until it has run once:
  * reading a name out of it would mean running it.
@@ -144,9 +144,7 @@ export class PluginsPane extends VStack {
     this.empty.visible = nothing;
     if (nothing && this.manager) this.empty.setText('No plugins in data/plugins');
     this.hint.setText(
-      nothing
-        ? ''
-        : 'Loaded from data/plugins, for everyone using this server. A new file stays off until switched on here.',
+      nothing ? '' : 'Loaded from data/plugins. The switch belongs to this project and is an undo step.',
     );
     this.scroll.relayoutContent();
     this.relayout();