chore: remove remotion and @remotion/player from dependencies

- Removed 'remotion' and '@remotion/player' from package.json
- Deleted Root.tsx (SSR composition registry, no longer needed for frontend)
- Updated build scripts to skip remotion:bundle step
- Kept @remotion/bundler and @remotion/renderer for server-side (Phase 4)
- Verified: electron-vite build passes cleanly

src/Root.tsx

@@ -1,48 +0,0 @@
-/**
- * Remotion Root — Entry point for bundler to discover compositions.
- *
- * This file is referenced by the server-side renderer bundle step.
- * It registers BrandComposition as a renderable Composition.
- */
-import React from 'react';
-import { Composition, Still, registerRoot } from 'remotion';
-import { BrandComposition } from './components/BrandComposition';
-import { RenderProps } from './types';
-
-export const RemotionRoot: React.FC = () => {
-  return (
-    <>
-      {/* Video composition — used for MP4/WebM rendering */}
-      <Composition
-        id="BrandVideo"
-        component={BrandComposition}
-        durationInFrames={150}
-        fps={30}
-        width={1080}
-        height={1080}
-        defaultProps={{
-          designMD: {} as any,
-          textOverlay: '',
-          timelineElements: [],
-          layers: [],
-        }}
-      />
-
-      {/* Still composition — used for PNG/JPEG rendering */}
-      <Still
-        id="BrandStill"
-        component={BrandComposition}
-        width={1080}
-        height={1080}
-        defaultProps={{
-          designMD: {} as any,
-          textOverlay: '',
-          timelineElements: [],
-          layers: [],
-        }}
-      />
-    </>
-  );
-};
-
-registerRoot(RemotionRoot);