Add Bun installation checks to Jenkins pipeline

- Introduced a function to ensure Bun is installed on both Unix and Windows environments.
- Updated the Jenkinsfile to call this function during the setup stages, improving the reliability of the build process.
- Ensured the PATH is correctly set for Bun after installation.

Jenkinsfile

@@ -2,6 +2,28 @@ properties([
     buildDiscarder(logRotator(numToKeepStr: '20'))
 ])
 
+def ensureBunInstalled() {
+    if (isUnix()) {
+        sh '''
+            set -euo pipefail
+            export BUN_INSTALL="${HOME}/.bun"
+            export PATH="${BUN_INSTALL}/bin:${PATH}"
+            if ! command -v bun >/dev/null 2>&1; then
+                curl -fsSL https://bun.sh/install | bash
+            fi
+            bun -v
+        '''
+        env.PATH = "${env.HOME}/.bun/bin:${env.PATH}"
+    } else {
+        bat '''
+            where bun >nul 2>nul || powershell -c "irm bun.sh/install.ps1 | iex"
+            set PATH=%USERPROFILE%\.bun\bin;%PATH%
+            bun -v
+        '''
+        env.PATH = "${env.USERPROFILE}\\.bun\\bin;${env.PATH}"
+    }
+}
+
 def writeBuildMetadata() {
     if (isUnix()) {
         sh '''
@@ -22,7 +44,7 @@ def buildLinux() {
             }
 
             stage('Setup Bun (Ubuntu)') {
-                sh 'bun -v'
+                ensureBunInstalled()
             }
 
             stage('Install Dependencies (Ubuntu)') {
@@ -54,11 +76,7 @@ def buildOnLabel(label, buildCommand) {
             }
 
             stage("Setup Bun (${label})") {
-                if (isUnix()) {
+                ensureBunInstalled()
-                    sh 'bun -v'
-                } else {
-                    bat 'bun -v'
-                }
             }
 
             stage("Install Dependencies (${label})") {
@@ -92,6 +110,7 @@ def setBuildNameFromPackageVersion() {
     node('ubuntu') {
         stage('Set Build Name') {
             checkout scm
+            ensureBunInstalled()
             def version = sh(
                 script: "bun --eval \"console.log(JSON.parse(await Bun.file('package.json').text()).version)\"",
                 returnStdout: true