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/arrays-hashing/0128-longest-consecutive-sequence.org

@@ -1,18 +1,62 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0128. Longest Consecutive Sequence :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0128. Longest Consecutive Sequence][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0128. Longest Consecutive Sequence][0128. Longest Consecutive Sequence]]
 :END:
 
+Given an unsorted array of integers ~nums~, return /the length of the longest consecutive elements sequence./
+
+You must write an algorithm that runs in ~O(n)~ time.
+
+*Example 1:*
+
+
+#+begin_src
+Input: nums = [100,4,200,1,3,2]
+Output: 4
+Explanation: The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is 4.
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: nums = [0,3,7,2,5,8,4,6,0,1]
+Output: 9
+#+end_src
+
+
+*Example 3:*
+
+
+#+begin_src
+Input: nums = [1,0,1,2]
+Output: 3
+#+end_src
+
+
+*Constraints:*
+
+ - ~0 <= nums.length <= 10^{5}~
+
+ - ~-10^{9} <= nums[i] <= 10^{9}~
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    int longestConsecutive(vector<int>& nums) {
+        
+    }
+};
 #+end_src