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/app-store/assets.ts

@@ -32,6 +32,9 @@ export const assetPublicDir = (sidecarId: string): string => join(process.cwd(),
 /** The URL a manifest should use for a shipped icon. */
 export const iconUrl = (sidecarId: string): string => `/plugins/${sidecarId}/icon.png`;
 
+/** The URL for a shipped splash. Published by the same copy — `publishAssets` takes the whole dir. */
+export const splashUrl = (sidecarId: string): string => `/plugins/${sidecarId}/splash.png`;
+
 const exists = async (path: string): Promise<boolean> => {
   try {
     await stat(path);