Add dynamic color theming from poster art using node-vibrant

Extract dominant colors from movie/TV poster images server-side and use
them to create per-title atmospheric effects on detail pages — tinted
backdrop gradients, ambient glow orbs, and colored poster shadows.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/db/schema.ts

@@ -91,6 +91,7 @@ export const titles = sqliteTable(
     voteAverage: real("voteAverage"),
     voteCount: int("voteCount"),
     status: text("status"),
+    colorPalette: text("colorPalette"),
     lastFetchedAt: int("lastFetchedAt", { mode: "timestamp" }),
   },
   (table) => [