docs: add React web client and "Building a React Wallet" tutorial

.gitignore

@@ -10,4 +10,4 @@ web-client/.next/
 web-client/playwright-report/
 web-client/test-results/
 **/.DS_Store
-.DS_Store
+.DS_Store

CLAUDE.md

@@ -0,0 +1,19 @@
+# Miden Tutorials
+
+## Markdown Formatting
+
+This repo has a CI check that enforces markdown formatting via Prettier.
+
+After making any changes to `.md` files, run:
+
+```sh
+npx prettier --check "**/*.md"
+```
+
+If it fails, fix with:
+
+```sh
+npx prettier --write "**/*.md"
+```
+
+The Prettier config is in `.prettierrc`. Files listed in `.prettierignore` are excluded from formatting.