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/intervals/0435-non-overlapping-intervals.org

@@ -1,18 +1,66 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0435. Non Overlapping Intervals :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0435. Non Overlapping Intervals][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0435. Non Overlapping Intervals][0435. Non Overlapping Intervals]]
 :END:
 
+Given an array of intervals ~intervals~ where ~intervals[i] = [start_{i}, end_{i}]~, return /the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping/.
+
+*Note* that intervals which only touch at a point are *non-overlapping*. For example, ~[1, 2]~ and ~[2, 3]~ are non-overlapping.
+
+*Example 1:*
+
+
+#+begin_src
+Input: intervals = [[1,2],[2,3],[3,4],[1,3]]
+Output: 1
+Explanation: [1,3] can be removed and the rest of the intervals are non-overlapping.
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: intervals = [[1,2],[1,2],[1,2]]
+Output: 2
+Explanation: You need to remove two [1,2] to make the rest of the intervals non-overlapping.
+#+end_src
+
+
+*Example 3:*
+
+
+#+begin_src
+Input: intervals = [[1,2],[2,3]]
+Output: 0
+Explanation: You don't need to remove any of the intervals since they're already non-overlapping.
+#+end_src
+
+
+*Constraints:*
+
+ - ~1 <= intervals.length <= 10^{5}~
+
+ - ~intervals[i].length == 2~
+
+ - ~-5 * 10^{4} <= start_{i} < end_{i} <= 5 * 10^{4}~
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    int eraseOverlapIntervals(vector<vector<int>>& intervals) {
+        
+    }
+};
 #+end_src