plugins: a splash is part of a plugin, like its icon

assets/splash.png is discovered by presence, published by the same copy that
already took the whole assets directory, and carried on DiscoveredPlugin beside
icon.

The platform draws no splash — a plugin has no launch. It is carried because the
plugin repository is where a product's artwork lives now, and the phone app that
fronts the same product needs somewhere to read it from that is not a designer's
folder. The pair is the point: the icon is a reduction of the splash's world,
and keeping them together is what stops them drifting.

Publishing no longer gates on the icon alone, which left a plugin shipping only
a splash serving nothing.

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

src/servers/plugins/discover.ts

@@ -106,6 +106,9 @@ export async function loadPlugin(dir: string, appName: string): Promise<Discover
     // could only ever name a glyph the platform had already bundled, which is a ceiling a plugin
     // from a marketplace has no way to see coming.
     icon: fileOrNull(join(dir, 'assets', 'icon.png')),
+    // The launch scene, carried for whoever fronts this plugin on a phone. Same rule as the icon:
+    // the file's presence is the declaration, and there is no manifest field to keep in step.
+    splash: fileOrNull(join(dir, 'assets', 'splash.png')),
     api: fileOrNull(join(dir, 'api', 'router.ts')),
     schema: fileOrNull(join(dir, 'db', 'schema.ts')),
     sidecar: findSidecar(dir),