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, 35 insertions, 0 deletions

diff --git a/apps/web/src/desktop/bridge.ts b/apps/web/src/desktop/bridge.ts
new file mode 100644
index 00000000..ea9f48f3
--- /dev/null
+++ b/apps/web/src/desktop/bridge.ts
@@ -0,0 +1,35 @@
+export type DesktopExportBegin = {
+	width: number;
+	height: number;
+	fpsNumerator: number;
+	fpsDenominator: number;
+	format: "mp4" | "webm";
+	quality: "low" | "medium" | "high" | "very_high";
+	hasAudio: boolean;
+	sampleRate: number;
+	channels: number;
+	defaultFileName: string;
+};
+
+export type OpenCutDesktop = {
+	isDesktop: true;
+	exportBegin: (
+		opts: DesktopExportBegin,
+	) => Promise<{ id: string; filePath: string } | null>;
+	exportWriteAudio: (id: string, pcm: ArrayBuffer) => Promise<void>;
+	exportWriteFrame: (id: string, rgba: ArrayBuffer) => Promise<void>;
+	exportFinish: (id: string) => Promise<void>;
+	exportCancel: (id: string) => Promise<void>;
+	revealFile: (path: string) => Promise<void>;
+};
+
+declare global {
+	interface Window {
+		opencutDesktop?: OpenCutDesktop;
+	}
+}
+
+export function getDesktopBridge(): OpenCutDesktop | null {
+	if (typeof window === "undefined") return null;
+	return window.opencutDesktop ?? null;
+}