feat: restore dynamic NCERT quiz with 505 questions from original repo

src/api/v1/quiz.py

@@ -0,0 +1,45 @@
+import re
+from fastapi import APIRouter
+from backend.src.math.knowledge_indexer import KnowledgeIndexer
+
+router = APIRouter()
+
+# Global cache for the quiz structure to avoid parsing markdown on every request
+_QUIZ_STRUCTURE_CACHE = None
+
+def build_quiz_structure():
+    global _QUIZ_STRUCTURE_CACHE
+    if _QUIZ_STRUCTURE_CACHE is not None:
+        return _QUIZ_STRUCTURE_CACHE
+
+    indexer = KnowledgeIndexer()
+    docs = indexer.load_markdown_files()
+    
+    quiz_tree = {}
+    
+    for doc in docs:
+        m = doc.metadata
+        cl = m.get("class_level", "")
+        ch = m.get("chapter", "")
+        ex = m.get("exercise", "")
+        
+        if not (cl and ch and ex):
+            continue
+            
+        # The exact same regex used in the original Streamlit app to extract Q1, Q2, etc.
+        qs = re.findall(r'Q\d+[^\n]*(?:\n(?!Q\d+)[^\n]*)*', doc.page_content)
+        
+        if qs:
+            if cl not in quiz_tree:
+                quiz_tree[cl] = {}
+            if ch not in quiz_tree[cl]:
+                quiz_tree[cl][ch] = {}
+            quiz_tree[cl][ch][ex] = qs
+            
+    _QUIZ_STRUCTURE_CACHE = quiz_tree
+    return quiz_tree
+
+@router.get("/structure")
+def get_quiz_structure():
+    """Returns the nested tree of Classes -> Chapters -> Exercises -> Questions"""
+    return build_quiz_structure()

src/main.py

@@ -80,6 +80,8 @@ app.add_middleware(
 app.include_router(chat.router)
 app.include_router(progress.router)
 
+from backend.src.api.v1 import quiz
+app.include_router(quiz.router, prefix="/api/v1/quiz", tags=["Quiz"])
 
 @app.get("/health")
 async def health_check():