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/math-geometry/0012-integer-to-roman.org

@@ -1,18 +1,114 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0012. Integer to Roman :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0012. Integer to Roman][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0012. Integer to Roman][0012. Integer to Roman]]
 :END:
 
+Seven different symbols represent Roman numerals with the following values:
+
+ Symbol
+ Value
+
+ I
+ 1
+
+ V
+ 5
+
+ X
+ 10
+
+ L
+ 50
+
+ C
+ 100
+
+ D
+ 500
+
+ M
+ 1000
+
+Roman numerals are formed by appending the conversions of decimal place values from highest to lowest. Converting a decimal place value into a Roman numeral has the following rules:
+
+ - If the value does not start with 4 or 9, select the symbol of the maximal value that can be subtracted from the input, append that symbol to the result, subtract its value, and convert the remainder to a Roman numeral.
+
+ - If the value starts with 4 or 9 use the *subtractive form* representing one symbol subtracted from the following symbol, for example, 4 is 1 (~I~) less than 5 (~V~): ~IV~ and 9 is 1 (~I~) less than 10 (~X~): ~IX~. Only the following subtractive forms are used: 4 (~IV~), 9 (~IX~), 40 (~XL~), 90 (~XC~), 400 (~CD~) and 900 (~CM~).
+
+ - Only powers of 10 (~I~, ~X~, ~C~, ~M~) can be appended consecutively at most 3 times to represent multiples of 10. You cannot append 5 (~V~), 50 (~L~), or 500 (~D~) multiple times. If you need to append a symbol 4 times use the *subtractive form*.
+
+Given an integer, convert it to a Roman numeral.
+
+*Example 1:*
+
+*Input:* num = 3749
+
+*Output:* "MMMDCCXLIX"
+
+*Explanation:*
+
+
+#+begin_src
+3000 = MMM as 1000 (M) + 1000 (M) + 1000 (M)
+ 700 = DCC as 500 (D) + 100 (C) + 100 (C)
+  40 = XL as 10 (X) less of 50 (L)
+   9 = IX as 1 (I) less of 10 (X)
+Note: 49 is not 1 (I) less of 50 (L) because the conversion is based on decimal places
+#+end_src
+
+
+*Example 2:*
+
+*Input:* num = 58
+
+*Output:* "LVIII"
+
+*Explanation:*
+
+
+#+begin_src
+50 = L
+ 8 = VIII
+#+end_src
+
+
+*Example 3:*
+
+*Input:* num = 1994
+
+*Output:* "MCMXCIV"
+
+*Explanation:*
+
+
+#+begin_src
+1000 = M
+ 900 = CM
+  90 = XC
+   4 = IV
+#+end_src
+
+
+*Constraints:*
+
+ - ~1 <= num <= 3999~
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def intToRoman(self, num: int) -> str:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    string intToRoman(int num) {
+        
+    }
+};
 #+end_src