feat: implement curriculum service and learning automation infrastructure

src/lib/learningService.js

@@ -56,13 +56,15 @@ export async function getAssignedTopic(userId, weekNumber) {
   // Try curriculum first
   try {
     const { topic } = await getCurriculumTopic(weekNumber);
-    if (topic) return topic;
+    if (topic && topic.learning_relevance !== 'exclude') return topic;
   } catch (e) {
     console.warn('[Learn] Curriculum lookup failed, falling back to hash:', e.message);
   }
 
   // Fallback: hash-based assignment (backwards compatible)
-  const topics = await db.getTopics();
+  const allTopics = await db.getTopics();
+  // Filter out 'fact' type topics and 'exclude' relevance topics
+  const topics = allTopics.filter(t => t.type !== 'fact' && t.learning_relevance !== 'exclude');
   if (!topics || topics.length === 0) return null;
 
   const str = `${userId}:${weekNumber}`;