fix: upgrade devDependencies and migrate to eslint 10 flat config

- Upgrade eslint 8.31 → 10.1 with new flat config (eslint.config.js)
- Upgrade @vercel/ncc 0.36 → 0.38.4
- Replace eslint-config-airbnb-base + eslint-plugin-import with @eslint/js + @stylistic/eslint-plugin
- Remove stale overrides in package.json (word-wrap, semver)
- Remove obsolete eslint-disable comments from source files
- Add { cause } to rethrown error in rsyncCli.js
- Add .gitignore and CLAUDE.md
- Resolves all 3 npm audit vulnerabilities (flatted, minimatch, js-yaml)

src/index.js

@@ -27,7 +27,6 @@ const run = async () => {
   if (scriptBefore) {
     await remoteCmdBefore(scriptBefore, privateKeyPath, scriptBeforeRequired);
   }
-  /* eslint-disable object-property-newline */
   await sshDeploy({
     source, rsyncServer, exclude, remotePort,
     privateKeyPath, args, sshCmdArgs

src/inputs.js

@@ -27,7 +27,6 @@ inputNames.forEach((input) => {
   const inputVal = process.env[input] || process.env[`INPUT_${input}`] || defaultInputs[inputName];
   const validVal = inputVal === undefined ? defaultInputs[inputName] : inputVal;
   let extendedVal = validVal;
-  // eslint-disable-next-line default-case
   switch (inputName) {
     case 'source':
       extendedVal = validVal.split(' ').map((src) => `${githubWorkspace}/${src}`);

src/remoteCmd.js

@@ -11,7 +11,6 @@ const handleError = (message, isRequired, callback) => {
   }
 };
 
-// eslint-disable-next-line max-len
 const remoteCmd = async (content, privateKeyPath, isRequired, label) => new Promise((resolve, reject) => {
   const uuid = crypto.randomUUID();
   const filename = `local_ssh_script-${label}-${uuid}.sh`;

src/rsyncCli.js

@@ -46,7 +46,7 @@ const validateRsync = async () => {
     execSync('sudo DEBIAN_FRONTEND=noninteractive apt-get -y update && sudo DEBIAN_FRONTEND=noninteractive apt-get --no-install-recommends -y install rsync', { stdio: 'inherit' });
     console.log('✅ [CLI] Rsync installed. \n');
   } catch (error) {
-    throw new Error(`⚠️ [CLI] Rsync installation failed. Aborting ... error: ${error.message}`);
+    throw new Error(`⚠️ [CLI] Rsync installation failed. Aborting ... error: ${error.message}`, { cause: error });
   }
 };
 
@@ -65,7 +65,6 @@ const rsyncCli = async ({
   };
 
   // RSYNC COMMAND
-  /* eslint-disable object-property-newline */
   return nodeRsyncPromise({
     ...defaultOptions,
     src: source, dest: rsyncServer, excludeFirst: exclude, port: remotePort,