feat: note scoring 60/6 with rating award + Minecraft theme

- Score max changed from 100 to 60, rating max from 10 to 6
- Note scoring now awards actual rating points (delta-based)
- Re-scoring only awards/deducts the difference
- Rating history shows note_score entries with problem link
- LLM prompt includes problem statement context for better evaluation
- LLM scoring dimensions: 题意理解/思路算法/代码记录/踩坑反思 (15 each)
- Minecraft-themed UI: 矿石鉴定, 探索笔记, 存入宝典, etc.
- Fallback scoring adjusted for 60-point scale
- Handle LLM markdown code fence wrapping in response

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/src/controllers/me_controller.cc

@@ -342,8 +342,17 @@ void MeController::scoreWrongBookNote(
     services::WrongBookService wrong_book(csp::AppState::Instance().db());
     // ensure note saved
     wrong_book.UpsertNote(*user_id, problem_id, note);
+
+    // Get previous score to calculate rating delta
+    const int prev_rating = wrong_book.GetNoteRating(*user_id, problem_id);
     wrong_book.UpsertNoteScore(*user_id, problem_id, result.score, result.rating, result.feedback_md);
 
+    // Award (or adjust) rating points: delta = new_rating - prev_rating
+    const int delta = result.rating - prev_rating;
+    if (delta != 0) {
+      wrong_book.AwardNoteRating(*user_id, problem_id, delta);
+    }
+
     Json::Value data;
     data["user_id"] = Json::Int64(*user_id);
     data["problem_id"] = Json::Int64(problem_id);