refactor(desktop): note the runtime descriptor validation in applyRelease

applyRelease keeps readDesktopRuntime for its fail-loud validation after the cleanup consumer was removed.

apps/desktop/src/project-manager.ts

@@ -82,6 +82,7 @@ export class DesktopProjectManager {
    */
   async applyRelease(): Promise<void> {
     await this.withLock(() => {
+      // Validation only: an unreadable or mismatched runtime descriptor stops preparation before the Host starts.
       readDesktopRuntime(this.runtime.dsh)
       migrateProfileSettings(this.paths.profile)
       createPluginProfile(this.paths.profile)