chore: update package version to 1.2.5 and add Jest testing framework

- Bump version in package.json and package-lock.json from 1.2.2 to 1.2.5
- Add Jest configuration file for testing
- Update build scripts to use npm instead of bun
- Add linting and testing scripts to package.json
- Include tsconfig files in package.json files array

package-lock.json

@@ -1,12 +1,13 @@
 {
   "name": "@siwats/mxrelay-consumer",
-  "version": "1.0.0",
+  "version": "1.2.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@siwats/mxrelay-consumer",
-      "version": "1.0.0",
+      "version": "1.2.2",
+      "hasInstallScript": true,
       "license": "MIT",
       "dependencies": {
         "nodemailer": "^7.0.5",