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/0073-set-matrix-zeroes.org

@@ -1,18 +1,67 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0073. Set Matrix Zeroes :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0073. Set Matrix Zeroes][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0073. Set Matrix Zeroes][0073. Set Matrix Zeroes]]
 :END:
 
+Given an ~m x n~ integer matrix ~matrix~, if an element is ~0~, set its entire row and column to ~0~'s.
+
+You must do it in place.
+
+*Example 1:*
+
+
+#+begin_src
+Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
+Output: [[1,0,1],[0,0,0],[1,0,1]]
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]
+Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]
+#+end_src
+
+
+*Constraints:*
+
+ - ~m == matrix.length~
+
+ - ~n == matrix[0].length~
+
+ - ~1 <= m, n <= 200~
+
+ - ~-2^{31} <= matrix[i][j] <= 2^{31} - 1~
+
+*Follow up:*
+
+ - A straightforward solution using ~O(mn)~ space is probably a bad idea.
+
+ - A simple improvement uses ~O(m + n)~ space, but still not the best solution.
+
+ - Could you devise a constant space solution?
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def setZeroes(self, matrix: List[List[int]]) -> None:
+        """
+        Do not return anything, modify matrix in-place instead.
+        """
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    void setZeroes(vector<vector<int>>& matrix) {
+        
+    }
+};
 #+end_src