The "upload_result Seite hat keinen filecode" error fired with no actionable
detail when Doodstream's CDN returned an empty filecode (fn). Root cause is
server-side: the page structure is unchanged, the link is just missing —
Doodstream's backend refused the file (copyright/hash match, duplicate, size,
quota). XFileSharing reports the reason in the `st` field, which we ignored.
- Surface `st`: non-OK status now throws "Doodstream lehnt Datei ab (Status: …)".
- Enrich the generic error with st, fn-state, and the CDN node for diagnosis.
- Fix debug-log path: wrote to __dirname/.. which is read-only (app.asar) in
packaged builds, so production captured zero traces. Now uses Electron's
writable userData dir, with repo-root fallback for tests/plain node.
- Add tests/doodstream-upload.test.js (4 tests) pinning the parse/error paths.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
