Add solution notes scaffold and sub-heading format

- roadmap.org: problems now have *** Python and *** C++ sub-headings,
  plus Notes: links to per-problem org files
- scaffold-notes.mjs: creates 199 note files in org/cpp/dsa/<topic>/
  with backlinks to roadmap.org
- 18 topic folders under org/cpp/dsa/ for NeetCode 150 problems
- Updated AGENTS.md with new conventions and workflow

org/cpp/dsa/advanced-graphs/0269-alien-dictionary.org

@@ -0,0 +1,8 @@
+* TODO 0269. Alien Dictionary :hard:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*0269. Alien Dictionary][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src

org/cpp/dsa/advanced-graphs/0332-reconstruct-itinerary.org

@@ -0,0 +1,8 @@
+* TODO 0332. Reconstruct Itinerary :hard:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*0332. Reconstruct Itinerary][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src

org/cpp/dsa/advanced-graphs/0743-network-delay-time.org

@@ -0,0 +1,8 @@
+* TODO 0743. Network Delay Time :medium:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*0743. Network Delay Time][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src

org/cpp/dsa/advanced-graphs/0778-swim-in-rising-water.org

@@ -0,0 +1,8 @@
+* TODO 0778. Swim In Rising Water :hard:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*0778. Swim In Rising Water][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src

org/cpp/dsa/advanced-graphs/0787-cheapest-flights-within-k-stops.org

@@ -0,0 +1,8 @@
+* TODO 0787. Cheapest Flights Within K Stops :medium:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*0787. Cheapest Flights Within K Stops][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src

org/cpp/dsa/advanced-graphs/1584-min-cost-to-connect-all-points.org

@@ -0,0 +1,8 @@
+* TODO 1584. Min Cost to Connect All Points :medium:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*1584. Min Cost to Connect All Points][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src

org/cpp/dsa/advanced-graphs/2493-divide-nodes-into-the-maximum-number-of-groups.org

@@ -0,0 +1,8 @@
+* TODO 2493. Divide Nodes Into the Maximum Number of Groups :hard:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*2493. Divide Nodes Into the Maximum Number of Groups][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src

org/cpp/dsa/advanced-graphs/2812-find-the-safest-path-in-a-grid.org

@@ -0,0 +1,8 @@
+* TODO 2812. Find the Safest Path in a Grid :medium:
+:PROPERTIES:
+:NEETCODE: [[../../../../leetcode/out/roadmap.org::*2812. Find the Safest Path in a Grid][Roadmap]]
+:END:
+
+#+begin_src cpp
+
+#+end_src