Add TODO checkboxes to Python/C++ sub-headings

- roadmap.org: *** TODO Python and *** TODO C++ with [/] cookie
  on each problem heading for [0/2] progress tracking
- Note files now have TODO Approach, TODO Python, TODO C++
  sections for structured problem solving

leetcode/scaffold-notes.mjs

@@ -24,7 +24,7 @@ for (const line of roadmap.split("\n")) {
   }
 
   const problemMatch = line.match(
-    /^\*\* TODO (\d+)\. (.+?) :(easy|medium|hard):$/
+    /^\*\* TODO (\d+)\. (.+?) :(easy|medium|hard): \[\/\]$/
   );
   if (problemMatch) {
     const [, num, name, diff] = problemMatch;
@@ -43,6 +43,15 @@ for (const line of roadmap.split("\n")) {
 :NEETCODE: [[${relPath}][Roadmap]]
 :END:
 
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
 #+begin_src cpp
 
 #+end_src