feat(islands): add StudyDeck component and markdown decks for algorithms

islands/decks/index.ts

@@ -0,0 +1,26 @@
+/**
+ * Markdown study decks rendered by the StudyDeck island (reveal.js).
+ *
+ * Each deck is a plain markdown file in this directory — edit the `.md`
+ * file to change its slides. Slides split on `---` lines; lists animate
+ * in one item at a time (see `animateLists` in StudyDeck.tsx). Problem
+ * numbers reference the curriculum in README.md and the solutions under
+ * `work/`.
+ */
+import arraysAndStrings from "./arrays-and-strings.md?raw";
+import binarySearch from "./binary-search.md?raw";
+import hashing from "./hashing.md?raw";
+import prefixSum from "./prefix-sum.md?raw";
+import slidingWindow from "./sliding-window.md?raw";
+import twoPointers from "./two-pointers.md?raw";
+
+export const decks = {
+  "arrays-and-strings": arraysAndStrings,
+  "binary-search": binarySearch,
+  hashing,
+  "prefix-sum": prefixSum,
+  "sliding-window": slidingWindow,
+  "two-pointers": twoPointers,
+} as const;
+
+export type DeckName = keyof typeof decks;