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/math-geometry/2326-spiral-matrix-iv.org

@@ -1,18 +1,79 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 2326. Spiral Matrix IV :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*2326. Spiral Matrix IV][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*2326. Spiral Matrix IV][2326. Spiral Matrix IV]]
 :END:
 
+You are given two integers ~m~ and ~n~, which represent the dimensions of a matrix.
+
+You are also given the ~head~ of a linked list of integers.
+
+Generate an ~m x n~ matrix that contains the integers in the linked list presented in *spiral* order *(clockwise)*, starting from the *top-left* of the matrix. If there are remaining empty spaces, fill them with ~-1~.
+
+Return /the generated matrix/.
+
+*Example 1:*
+
+
+#+begin_src
+Input: m = 3, n = 5, head = [3,0,2,6,8,1,7,9,4,2,5,5,0]
+Output: [[3,0,2,6,8],[5,0,-1,-1,1],[5,2,4,9,7]]
+Explanation: The diagram above shows how the values are printed in the matrix.
+Note that the remaining spaces in the matrix are filled with -1.
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: m = 1, n = 4, head = [0,1,2]
+Output: [[0,1,2,-1]]
+Explanation: The diagram above shows how the values are printed from left to right in the matrix.
+The last space in the matrix is set to -1.
+#+end_src
+
+
+*Constraints:*
+
+ - ~1 <= m, n <= 10^{5}~
+
+ - ~1 <= m * n <= 10^{5}~
+
+ - The number of nodes in the list is in the range ~[1, m * n]~.
+
+ - ~0 <= Node.val <= 1000~
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def spiralMatrix(self, m: int, n: int, head: Optional[ListNode]) -> List[List[int]]:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode() : val(0), next(nullptr) {}
+ *     ListNode(int x) : val(x), next(nullptr) {}
+ *     ListNode(int x, ListNode *next) : val(x), next(next) {}
+ * };
+ */
+class Solution {
+public:
+    vector<vector<int>> spiralMatrix(int m, int n, ListNode* head) {
+        
+    }
+};
 #+end_src