feat(wails): add native file dialogs and video streaming

FileService exposes open/save dialogs for video, project JSON, and WAV
export. User-selected videos stream from disk at /localmedia/video with
range request support for seeking in the webview.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/bindings/github.com/wailsapp/wails/v3/internal/eventcreate.ts

@@ -0,0 +1,9 @@
+//@ts-check
+// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
+// This file is automatically generated. DO NOT EDIT
+
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore: Unused imports
+import { Create as $Create } from "@wailsio/runtime";
+
+Object.freeze($Create.Events);