feat: add shared types package

packages/shared/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "@codeboard/shared",
+  "version": "0.0.1",
+  "private": true,
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc",
+    "clean": "rm -rf dist",
+    "dev": "tsc --watch"
+  },
+  "devDependencies": {
+    "typescript": "^5.7"
+  }
+}