chore: add prettier and format all files

- Install prettier ^3.6.2
- Add .prettierrc with project formatting rules
- Add .prettierignore to exclude generated files and dependencies
- Add npm scripts: format and format:check
- Format all files with prettier

.prettierrc

@@ -0,0 +1,11 @@
+{
+  "semi": true,
+  "trailingComma": "all",
+  "singleQuote": false,
+  "printWidth": 100,
+  "tabWidth": 2,
+  "useTabs": false,
+  "arrowParens": "always",
+  "endOfLine": "lf",
+  "proseWrap": "preserve"
+}