feat(remotion): upgrade cinematic TitleCard + add new scene components

- CinematicRenderer.tsx / cinematic/types.ts: TitleCard now supports
  ghosted video background, word-by-word stagger reveal with blur->sharp
  transition, proper newline handling, and growing accent lines. Title
  scenes accept backgroundSrc/backgroundTrimBeforeSeconds/
  backgroundTrimAfterSeconds plus a plate|overlay variant.
- Add CollageBurst, LyricOverlay, ScreenshotScene components.
- Explainer, Root, components/index.ts wiring updates.
- SCENE_TYPES.md reflects the new components.
- seedance-2-0 skill + seedance_video.py: small fixes.

remotion-composer/src/cinematic/types.ts

@@ -22,6 +22,10 @@ export interface CinematicTitleScene extends CinematicBaseScene {
   text: string;
   accent?: string;
   intensity?: number;
+  backgroundSrc?: string;
+  backgroundTrimBeforeSeconds?: number;
+  backgroundTrimAfterSeconds?: number;
+  variant?: "plate" | "overlay";
 }
 
 export type CinematicScene = CinematicVideoScene | CinematicTitleScene;