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/sliding-window/0567-permutation-in-string.org

@@ -1,18 +1,53 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0567. Permutation In String :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0567. Permutation In String][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0567. Permutation In String][0567. Permutation In String]]
 :END:
 
+Given two strings ~s1~ and ~s2~, return ~true~ if ~s2~ contains a permutation of ~s1~, or ~false~ otherwise.
+
+In other words, return ~true~ if one of ~s1~'s permutations is the substring of ~s2~.
+
+*Example 1:*
+
+
+#+begin_src
+Input: s1 = "ab", s2 = "eidbaooo"
+Output: true
+Explanation: s2 contains one permutation of s1 ("ba").
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: s1 = "ab", s2 = "eidboaoo"
+Output: false
+#+end_src
+
+
+*Constraints:*
+
+ - ~1 <= s1.length, s2.length <= 10^{4}~
+
+ - ~s1~ and ~s2~ consist of lowercase English letters.
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def checkInclusion(self, s1: str, s2: str) -> bool:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    bool checkInclusion(string s1, string s2) {
+        
+    }
+};
 #+end_src