Wire Infographic URLs from Sanity → Pipeline → Remotion

The InfographicScene component (PR #631) was merged but never received data — the pipeline wasn't reading infographic URLs from the Sanity doc or passing them to Remotion.

Problem

Sanity doc has infographics[] ──✗──> video-pipeline.ts ──✗──> remotion.ts ──✗──> SceneRouter
                                     (never read)           (never mapped)      (never rendered)

Fix

Sanity doc has infographics[] ──✓──> video-pipeline.ts ──✓──> remotion.ts ──✓──> SceneRouter → InfographicScene
                                     (getInfographicUrls)   (mapInputProps)     (Ken Burns zoom/pan)

Changes

lib/services/video-pipeline.ts (+71 lines):

• Added getInfographicUrls(doc) helper with two strategies:
  1. Primary: Resolve doc.infographics[] Sanity image assets via @sanity/image-url
  2. Fallback: Parse doc.researchData JSON → extract infographicUrls[]
• Wrapped in try/catch — never fails the pipeline over missing infographics
• Round-robin distribution across scenes: infographicUrls[i % infographicUrls.length]
• Only sets infographicUrl when URLs exist — scenes without infographics fall through to Pexels B-roll

lib/services/remotion.ts (+2 lines):

• Added infographicUrl?: string to RenderInput.script.scenes type
• Conditional spread in mapInputProps(): only includes infographicUrl when truthy (avoids empty string failing Zod .url().optional())

Scope

✅ 2 files, both in my ownership. No other files touched.