feat: populate note files with problem descriptions and code stubs

Add populate-notes.mjs that fetches problem descriptions and
Python/C++ code stubs from LeetCode's GraphQL API. Populated
all 197 NeetCode 150 note files with:
- Problem description (examples, constraints)
- Python code stub (function signature)
- C++ code stub (function signature + includes)

API responses cached in leetcode/.cache/leetcode/ for instant re-runs.

org/study_deck_02/dsa/graphs/0210-course-schedule-ii.org

@@ -1,18 +1,74 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0210. Course Schedule II :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0210. Course Schedule II][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0210. Course Schedule II][0210. Course Schedule II]]
 :END:
 
+There are a total of ~numCourses~ courses you have to take, labeled from ~0~ to ~numCourses - 1~. You are given an array ~prerequisites~ where ~prerequisites[i] = [a_{i}, b_{i}]~ indicates that you *must* take course ~b_{i}~ first if you want to take course ~a_{i}~.
+
+ - For example, the pair ~[0, 1]~, indicates that to take course ~0~ you have to first take course ~1~.
+
+Return /the ordering of courses you should take to finish all courses/. If there are many valid answers, return *any* of them. If it is impossible to finish all courses, return *an empty array*.
+
+*Example 1:*
+
+
+#+begin_src
+Input: numCourses = 2, prerequisites = [[1,0]]
+Output: [0,1]
+Explanation: There are a total of 2 courses to take. To take course 1 you should have finished course 0. So the correct course order is [0,1].
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: numCourses = 4, prerequisites = [[1,0],[2,0],[3,1],[3,2]]
+Output: [0,2,1,3]
+Explanation: There are a total of 4 courses to take. To take course 3 you should have finished both courses 1 and 2. Both courses 1 and 2 should be taken after you finished course 0.
+So one correct course order is [0,1,2,3]. Another correct ordering is [0,2,1,3].
+#+end_src
+
+
+*Example 3:*
+
+
+#+begin_src
+Input: numCourses = 1, prerequisites = []
+Output: [0]
+#+end_src
+
+
+*Constraints:*
+
+ - ~1 <= numCourses <= 2000~
+
+ - ~0 <= prerequisites.length <= numCourses * (numCourses - 1)~
+
+ - ~prerequisites[i].length == 2~
+
+ - ~0 <= a_{i}, b_{i} < numCourses~
+
+ - ~a_{i} != b_{i}~
+
+ - All the pairs ~[a_{i}, b_{i}]~ are *distinct*.
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def findOrder(self, numCourses: int, prerequisites: List[List[int]]) -> List[int]:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    vector<int> findOrder(int numCourses, vector<vector<int>>& prerequisites) {
+        
+    }
+};
 #+end_src