refactor: move DSA notes to org/study_deck_02/

Restructure NeetCode study materials into a dedicated Anki-exportable
deck directory. Separates DSA problem notes from C++ flashcards.

- Move roadmap.org from leetcode/out/ to org/study_deck_02/
- Move 200 note files from org/cpp/dsa/ to org/study_deck_02/dsa/
- Add #+PROPERTY: STUDY_DECK_02 to all org files for org-anki export
- Simplify roadmap format: properties drawer replaces nested headings
- Update NEETCODE backlinks in all note files
- Update extract.mjs and scaffold-notes.mjs for new paths
- Create org/study_deck_02/AGENTS.md with study workflow docs
- Update root and leetcode AGENTS.md

org/study_deck_02/dsa/binary-search/0004-median-of-two-sorted-arrays.org

@@ -0,0 +1,18 @@
+* TODO 0004. Median of Two Sorted Arrays :hard:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0004. Median of Two Sorted Arrays][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/0033-search-in-rotated-sorted-array.org

@@ -0,0 +1,18 @@
+* TODO 0033. Search In Rotated Sorted Array :medium:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0033. Search In Rotated Sorted Array][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/0074-search-a-2d-matrix.org

@@ -0,0 +1,18 @@
+* TODO 0074. Search a 2D Matrix :medium:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0074. Search a 2D Matrix][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/0153-find-minimum-in-rotated-sorted-array.org

@@ -0,0 +1,18 @@
+* TODO 0153. Find Minimum In Rotated Sorted Array :medium:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0153. Find Minimum In Rotated Sorted Array][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/0704-binary-search.org

@@ -0,0 +1,18 @@
+* TODO 0704. Binary Search :easy:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0704. Binary Search][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/0719-find-k-th-smallest-pair-distance.org

@@ -0,0 +1,18 @@
+* TODO 0719. Find K-th Smallest Pair Distance :hard:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0719. Find K-th Smallest Pair Distance][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/0875-koko-eating-bananas.org

@@ -0,0 +1,18 @@
+* TODO 0875. Koko Eating Bananas :medium:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0875. Koko Eating Bananas][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/0981-time-based-key-value-store.org

@@ -0,0 +1,18 @@
+* TODO 0981. Time Based Key Value Store :medium:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*0981. Time Based Key Value Store][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src

org/study_deck_02/dsa/binary-search/2300-successful-pairs-of-spells-and-potions.org

@@ -0,0 +1,18 @@
+* TODO 2300. Successful Pairs of Spells and Potions :medium:
+#+PROPERTY: STUDY_DECK_02
+:PROPERTIES:
+:NEETCODE: [[../../roadmap.org::*2300. Successful Pairs of Spells and Potions][Roadmap]]
+:END:
+
+** TODO Approach
+Write your approach here.
+
+** TODO Python
+#+begin_src python
+
+#+end_src
+
+** TODO C++
+#+begin_src cpp
+
+#+end_src