Fix gap #22 and add CinematicRenderer captions + music support

- AGENT_GUIDE.md: add "never read source code" rule — skills are the
  interface, not .py files
- animation.yaml: add Layer 2 skill-first guardrail in assets stage
- video-reference-analyst.md: Step 4b now mandates Layer 2 before Layer 3,
  explicitly forbids reading implementation code
- CinematicRenderer: add TikTok-style CaptionOverlay and separate music
  track support (narration + music as independent audio layers)
- cinematic/types.ts: add CinematicCaptionConfig and music prop types

remotion-composer/src/cinematic/types.ts

@@ -35,6 +35,21 @@ export interface CinematicSoundtrack {
   fadeOutSeconds?: number;
 }
 
+export interface CinematicWordCaption {
+  word: string;
+  startMs: number;
+  endMs: number;
+}
+
+export interface CinematicCaptionConfig {
+  words: CinematicWordCaption[];
+  wordsPerPage?: number;
+  fontSize?: number;
+  color?: string;
+  highlightColor?: string;
+  backgroundColor?: string;
+}
+
 export interface CinematicRendererProps {
   [key: string]: unknown;
   scenes: CinematicScene[];
@@ -42,4 +57,6 @@ export interface CinematicRendererProps {
   titleWidth?: number;
   signalLineCount?: number;
   soundtrack?: CinematicSoundtrack;
+  music?: CinematicSoundtrack;
+  captions?: CinematicCaptionConfig;
 }