feat: implement AI-driven learning content generation service and interactive leaderboard functionality

src/lib/learningService.js

@@ -156,3 +156,38 @@ Apply the refinement and return the complete updated JSON object using the same
 export function deleteCachedContent(topicId) {
   storage.remove(getContentCacheKey(topicId));
 }
+
+/**
+ * Generate a new custom topic metadata on the fly from user input.
+ */
+export async function generateCustomTopic(label) {
+  const prompt = `A user wants to learn about "${label}". 
+Create a short description (2-3 sentences) and categorize it.
+
+Return ONLY a JSON object with this structure:
+{
+  "label": "Polished topic title",
+  "type": "concept", // one of: concept, role, process, fact
+  "description": "Short description"
+}`;
+
+  const responseText = await anthropicApi.generateContent(
+    "You are a knowledge graph AI categorizing topics.", 
+    prompt
+  );
+
+  let newTopic;
+  try {
+    const jsonMatch = responseText.match(/\{[\s\S]*\}/);
+    newTopic = JSON.parse(jsonMatch ? jsonMatch[0] : responseText);
+    newTopic.id = 'custom_' + Date.now().toString(36);
+  } catch (e) {
+    throw new Error('Could not process custom topic. Please try again.');
+  }
+
+  // Add to global knowledge base so others can see it too
+  const topics = storage.get('kb:topics', []);
+  storage.set('kb:topics', [...topics, newTopic]);
+
+  return newTopic;
+}