fix(ota): harden desktop sync and updater flow

.github/scripts/build-ota-release.mjs

@@ -633,7 +633,7 @@ async function collectDesktopRendererPayload(input) {
     },
     launchAsset: await resolveFileAsset({
       sourcePath: rendererArchivePath,
-      metadataPath: join("renderer", filename),
+      metadataPath: filename,
     }),
     assets: [],
   }

.github/scripts/build-ota-release.test.ts

@@ -429,7 +429,7 @@ releaseDate: 2026-04-11T10:00:00.000Z
             "https://github.com/RSSNext/Folo/releases/download/desktop/v1.5.1/manifest.yml",
         },
         launchAsset: expect.objectContaining({
-          path: "renderer/custom-renderer.tar.gz",
+          path: "custom-renderer.tar.gz",
           contentType: "application/gzip",
         }),
       }),