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/binary-search/0074-search-a-2d-matrix.org

@@ -1,18 +1,62 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0074. Search a 2D Matrix :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0074. Search a 2D Matrix][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0074. Search a 2D Matrix][0074. Search a 2D Matrix]]
 :END:
 
+You are given an ~m x n~ integer matrix ~matrix~ with the following two properties:
+
+ - Each row is sorted in non-decreasing order.
+
+ - The first integer of each row is greater than the last integer of the previous row.
+
+Given an integer ~target~, return ~true~ /if/ ~target~ /is in/ ~matrix~ /or/ ~false~ /otherwise/.
+
+You must write a solution in ~O(log(m * n))~ time complexity.
+
+*Example 1:*
+
+
+#+begin_src
+Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 3
+Output: true
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 13
+Output: false
+#+end_src
+
+
+*Constraints:*
+
+ - ~m == matrix.length~
+
+ - ~n == matrix[i].length~
+
+ - ~1 <= m, n <= 100~
+
+ - ~-10^{4} <= matrix[i][j], target <= 10^{4}~
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    bool searchMatrix(vector<vector<int>>& matrix, int target) {
+        
+    }
+};
 #+end_src