Refactor: Centralize prompt builders

src/core/messages.js

@@ -0,0 +1,15 @@
+export const MASTER_PROMPT =
+  'minimal black and white line doodle, single stroke, white background, kawaii style';
+
+export function buildFirstMessage(userPrompt) {
+  return { role: 'user', content: `${MASTER_PROMPT}, ${userPrompt}` };
+}
+
+export function buildNextMessage(frameIndex, frameCount) {
+  return {
+    role: 'user',
+    content:
+      `imagine we are trying to create a ${frameCount} frame gif. ` +
+      `generate the next meaningful frame (frame ${frameIndex} of ${frameCount})`
+  };
+}