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/graphs/0684-redundant-connection.org

@@ -1,18 +1,64 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0684. Redundant Connection :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0684. Redundant Connection][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0684. Redundant Connection][0684. Redundant Connection]]
 :END:
 
+In this problem, a tree is an *undirected graph* that is connected and has no cycles.
+
+You are given a graph that started as a tree with ~n~ nodes labeled from ~1~ to ~n~, with one additional edge added. The added edge has two *different* vertices chosen from ~1~ to ~n~, and was not an edge that already existed. The graph is represented as an array ~edges~ of length ~n~ where ~edges[i] = [a_{i}, b_{i}]~ indicates that there is an edge between nodes ~a_{i}~ and ~b_{i}~ in the graph.
+
+Return /an edge that can be removed so that the resulting graph is a tree of /~n~/ nodes/. If there are multiple answers, return the answer that occurs last in the input.
+
+*Example 1:*
+
+
+#+begin_src
+Input: edges = [[1,2],[1,3],[2,3]]
+Output: [2,3]
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: edges = [[1,2],[2,3],[3,4],[1,4],[1,5]]
+Output: [1,4]
+#+end_src
+
+
+*Constraints:*
+
+ - ~n == edges.length~
+
+ - ~3 <= n <= 1000~
+
+ - ~edges[i].length == 2~
+
+ - ~1 <= a_{i} < b_{i} <= edges.length~
+
+ - ~a_{i} != b_{i}~
+
+ - There are no repeated edges.
+
+ - The given graph is connected.
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def findRedundantConnection(self, edges: List[List[int]]) -> List[int]:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    vector<int> findRedundantConnection(vector<vector<int>>& edges) {
+        
+    }
+};
 #+end_src