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/0417-pacific-atlantic-water-flow.org

@@ -1,18 +1,77 @@
 #+PROPERTY: STUDY_DECK_02
 * TODO 0417. Pacific Atlantic Water Flow :medium:
 :PROPERTIES:
-:NEETCODE: [[file:../../roadmap.org::*0417. Pacific Atlantic Water Flow][Roadmap]]
+:NEETCODE: [[file:../../roadmap.org::*0417. Pacific Atlantic Water Flow][0417. Pacific Atlantic Water Flow]]
 :END:
 
+There is an ~m x n~ rectangular island that borders both the *Pacific Ocean* and *Atlantic Ocean*. The *Pacific Ocean* touches the island's left and top edges, and the *Atlantic Ocean* touches the island's right and bottom edges.
+
+The island is partitioned into a grid of square cells. You are given an ~m x n~ integer matrix ~heights~ where ~heights[r][c]~ represents the *height above sea level* of the cell at coordinate ~(r, c)~.
+
+The island receives a lot of rain, and the rain water can flow to neighboring cells directly north, south, east, and west if the neighboring cell's height is *less than or equal to* the current cell's height. Water can flow from any cell adjacent to an ocean into the ocean.
+
+Return /a *2D list* of grid coordinates /~result~/ where /~result[i] = [r_{i}, c_{i}]~/ denotes that rain water can flow from cell /~(r_{i}, c_{i})~/ to *both* the Pacific and Atlantic oceans/.
+
+*Example 1:*
+
+
+#+begin_src
+Input: heights = [[1,2,2,3,5],[3,2,3,4,4],[2,4,5,3,1],[6,7,1,4,5],[5,1,1,2,4]]
+Output: [[0,4],[1,3],[1,4],[2,2],[3,0],[3,1],[4,0]]
+Explanation: The following cells can flow to the Pacific and Atlantic oceans, as shown below:
+[0,4]: [0,4] -> Pacific Ocean 
+       [0,4] -> Atlantic Ocean
+[1,3]: [1,3] -> [0,3] -> Pacific Ocean 
+       [1,3] -> [1,4] -> Atlantic Ocean
+[1,4]: [1,4] -> [1,3] -> [0,3] -> Pacific Ocean 
+       [1,4] -> Atlantic Ocean
+[2,2]: [2,2] -> [1,2] -> [0,2] -> Pacific Ocean 
+       [2,2] -> [2,3] -> [2,4] -> Atlantic Ocean
+[3,0]: [3,0] -> Pacific Ocean 
+       [3,0] -> [4,0] -> Atlantic Ocean
+[3,1]: [3,1] -> [3,0] -> Pacific Ocean 
+       [3,1] -> [4,1] -> Atlantic Ocean
+[4,0]: [4,0] -> Pacific Ocean 
+       [4,0] -> Atlantic Ocean
+Note that there are other possible paths for these cells to flow to the Pacific and Atlantic oceans.
+#+end_src
+
+
+*Example 2:*
+
+
+#+begin_src
+Input: heights = [[1]]
+Output: [[0,0]]
+Explanation: The water can flow from the only cell to the Pacific and Atlantic oceans.
+#+end_src
+
+
+*Constraints:*
+
+ - ~m == heights.length~
+
+ - ~n == heights[r].length~
+
+ - ~1 <= m, n <= 200~
+
+ - ~0 <= heights[r][c] <= 10^{5}~
+
 ** TODO Approach
 Write your approach here.
 
 ** TODO Python
 #+begin_src python
-
+class Solution:
+    def pacificAtlantic(self, heights: List[List[int]]) -> List[List[int]]:
 #+end_src
 
 ** TODO C++
 #+begin_src cpp
-
+class Solution {
+public:
+    vector<vector<int>> pacificAtlantic(vector<vector<int>>& heights) {
+        
+    }
+};
 #+end_src