feat: Electron desktop app, native ffmpeg export, fully static web

- apps/desktop: Electron shell serving the static web build over a
  privileged opencut:// protocol; exports stream frames over IPC to a
  bundled ffmpeg (libx264/libvpx-vp9, BT.709 tagged) with backpressure.
  electron-builder packaging: AppImage, deb, rpm.
- apps/web: dead backend deleted (better-auth, drizzle/pg, upstash,
  botid, freesound proxy, blog, rss, env validation); next build emits
  a zero-env static export; /editor/[project_id] -> /editor?project=.
- Native exporter mirrors SceneExporter; activates when the preload
  bridge is present; web keeps the mediabunny path.
- Docker self-hosting now builds and serves the static export via nginx.
- Release workflow: v* tags publish static web tarball + Linux packages.
- Changelog 0.4.0; README/AGENTS/CONTRIBUTING/roadmap updated.
- GPUI/Rust rewrite parked on branch rust-rewrite.

1 files changed, 1 insertions, 0 deletions

diff --git a/apps/web/src/export/index.ts b/apps/web/src/export/index.ts
index c5c522b3..1d91dbca 100644
--- a/apps/web/src/export/index.ts
+++ b/apps/web/src/export/index.ts
@@ -23,6 +23,7 @@ export interface ExportOptions {
 export interface ExportResult {
 	success: boolean;
 	buffer?: ArrayBuffer;
+	filePath?: string;
 	error?: string;
 	cancelled?: boolean;
 }