fix: Add ARM64 architecture support for Linux CLI downloads [IDE-1473] (#734)

fix: Add ARM64 architecture support for Linux CLI downloads

Fixes IDE-1473

IntelliJ on Linux ARM64 systems (aarch64) was incorrectly downloading
snyk-linux instead of snyk-linux-arm64, causing Language Server
initialization failures.

Changes:
- Added LINUX_ARM64 platform for snyk-linux-arm64 binary
- Added LINUX_ALPINE_ARM64 platform for snyk-alpine-arm64 binary
- Updated platform detection to check architecture (aarch64/arm64)
- Enhanced tests to cover all Linux architecture combinations

The plugin now correctly detects and downloads the appropriate CLI
binary for:
- Alpine + ARM64 → snyk-alpine-arm64
- ARM64 (non-Alpine) → snyk-linux-arm64
- Alpine (non-ARM64) → snyk-alpine
- Regular Linux → snyk-linux

Author: bastiandoetsch

src/main/kotlin/io/snyk/plugin/cli/Platform.kt

@@ -8,6 +8,8 @@ class Platform(val snykWrapperFileName: String) {
     companion object {
         val LINUX = Platform("snyk-linux")
         val LINUX_ALPINE = Platform("snyk-alpine")
+        val LINUX_ARM64 = Platform("snyk-linux-arm64")
+        val LINUX_ALPINE_ARM64 = Platform("snyk-alpine-arm64")
         val MAC_OS = Platform("snyk-macos")
         val MAC_OS_ARM64 = Platform("snyk-macos-arm64")
         val WINDOWS = Platform("snyk-win.exe")
@@ -20,7 +22,17 @@ class Platform(val snykWrapperFileName: String) {
             val osName = (systemProperties["os.name"] as String).lowercase()
             val archName = (systemProperties["os.arch"] as String).lowercase()
             return when (osName) {
-                "linux" -> if (Paths.get("/etc/alpine-release").toFile().exists()) LINUX_ALPINE else LINUX
+                "linux" -> {
+                    val isAlpine = Paths.get("/etc/alpine-release").toFile().exists()
+                    val isArm64 = archName == "aarch64" || archName == "arm64"
+                    
+                    when {
+                        isAlpine && isArm64 -> LINUX_ALPINE_ARM64
+                        isArm64 -> LINUX_ARM64
+                        isAlpine -> LINUX_ALPINE
+                        else -> LINUX
+                    }
+                }
                 "mac os x", "darwin", "osx" -> if (archName != "aarch64") MAC_OS else MAC_OS_ARM64
                 else -> {
                     if (osName.contains("windows")) {

src/test/kotlin/io/snyk/plugin/cli/PlatformTest.kt

@@ -16,7 +16,18 @@ class PlatformTest {
         val linuxPlatform = Platform.detect(properties)
         assertTrue(Platform.LINUX == linuxPlatform || Platform.LINUX_ALPINE == linuxPlatform)
 
+        properties["os.name"] = "linux"
+        properties["os.arch"] = "aarch64"
+        val arm64Platform = Platform.detect(properties)
+        assertTrue(Platform.LINUX_ARM64 == arm64Platform || Platform.LINUX_ALPINE_ARM64 == arm64Platform)
+
+        properties["os.name"] = "linux"
+        properties["os.arch"] = "arm64"
+        val arm64Platform2 = Platform.detect(properties)
+        assertTrue(Platform.LINUX_ARM64 == arm64Platform2 || Platform.LINUX_ALPINE_ARM64 == arm64Platform2)
+
         properties["os.name"] = "mac os x"
+        properties["os.arch"] = "something"
         assertTrue(Platform.MAC_OS == Platform.detect(properties))
 
         properties["os.name"] = "osx"