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/1408-string-matching-in-an-array.org

@@ -1,18 +1,67 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 1408. String Matching in an Array :easy:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*1408. String Matching in an Array][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*1408. String Matching in an Array][1408. String Matching in an Array]]
 :END:
 
+Given an array of string ~words~, return all strings in/ /~words~/ /that are a substring of another word. You can return the answer in *any order*.
+
+*Example 1:*
+
+
+#+begin_src
+Input: words = ["mass","as","hero","superhero"]
+Output: ["as","hero"]
+Explanation: "as" is substring of "mass" and "hero" is substring of "superhero".
+["hero","as"] is also a valid answer.
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: words = ["leetcode","et","code"]
+Output: ["et","code"]
+Explanation: "et", "code" are substring of "leetcode".
+#+end_src
+
+
+*Example 3:*
+
+
+#+begin_src
+Input: words = ["blue","green","bu"]
+Output: []
+Explanation: No string of words is substring of another string.
+#+end_src
+
+
+*Constraints:*
+
+ - ~1 <= words.length <= 100~
+
+ - ~1 <= words[i].length <= 30~
+
+ - ~words[i]~ contains only lowercase English letters.
+
+ - All the strings of ~words~ are *unique*.
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def stringMatching(self, words: List[str]) -> List[str]:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    vector<string> stringMatching(vector<string>& words) {
+        
+    }
+};
 #+end_src