docs(docs): restructure documentation paths and add new introduction file

docs/02-arrays-and-strings/02-two-pointers.mdx

@@ -0,0 +1,24 @@
+---
+title: 'Two Pointers'
+description: 'Converging/parallel index walk that prunes the O(n^2) pair space using order.'
+sidebar:
+  icon: sticky-note
+---
+
+:::warning[Under construction]
+This page is a scaffold. Notes, canonical problems, and template code are not written yet.
+:::
+
+## Concepts
+
+
+
+
+## Problems
+
+<CardGroup cols={2}>
+  <Card title="344. Reverse String" href="/problems/reverse-string">
+  </Card>
+  <Card title="977. Squares of a Sorted Array" href="/problems/squares-of-a-sorted-array">
+  </Card>
+</CardGroup>