fix: add exports field to package.json for ESM/CJS resolution

Resolves SSR ERR_MODULE_NOT_FOUND by exposing explicit import/require
conditions. Also corrects "module" and "types" paths to match the
actual tsdown output (.mjs / .d.cts).

Closes #584

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: yoannfleurydev

package.json

@@ -18,8 +18,20 @@
     "dist/"
   ],
   "main": "./dist/index.cjs",
-  "module": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "module": "./dist/index.mjs",
+  "types": "./dist/index.d.cts",
+  "exports": {
+    ".": {
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.cts",
+        "default": "./dist/index.cjs"
+      }
+    }
+  },
   "scripts": {
     "dev": "tsdown index.ts --format esm,cjs --dts --watch",
     "build": "tsdown index.ts --format esm,cjs --dts --minify",