Fix gateway detekt issues: replace deprecated launchIOBackground with coroutines

- Replace launchIOBackground with CoroutineScope and getCoroutineBgContext()
- Fix BannedImports rule by using contexts.kt utilities instead of Dispatchers
- Fix import ordering and remove unused imports
- Resolves gateway detekt failures for 2025.3 compatibility

Author: aseemxs

plugins/toolkit/jetbrains-gateway/src/software/aws/toolkits/jetbrains/gateway/CawsConnectionProvider.kt

@@ -11,8 +11,6 @@ import com.intellij.openapi.components.service
 import com.intellij.openapi.progress.ProcessCanceledException
 import com.intellij.openapi.progress.ProgressIndicator
 import com.intellij.openapi.rd.createNestedDisposable
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.launch
 import com.intellij.openapi.rd.util.launchOnUi
 import com.intellij.openapi.rd.util.startUnderBackgroundProgressAsync
 import com.intellij.openapi.rd.util.startUnderModalProgressAsync
@@ -36,6 +34,8 @@ import com.jetbrains.rd.framework.util.launch
 import com.jetbrains.rd.util.lifetime.Lifetime
 import com.jetbrains.rd.util.lifetime.LifetimeDefinition
 import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.coroutineScope
 import org.jetbrains.concurrency.AsyncPromise
 import org.jetbrains.concurrency.await
@@ -92,6 +92,8 @@ import software.aws.toolkits.telemetry.Result as TelemetryResult
 
 @ExperimentalTime
 class CawsConnectionProvider : GatewayConnectionProvider {
+    private val scope = CoroutineScope(getCoroutineBgContext() + SupervisorJob())
+
     companion object {
         val CAWS_CONNECTION_PARAMETERS = AttributeBagKey.create<Map<String, String>>("CAWS_CONNECTION_PARAMETERS")
         private val LOG = getLogger<CawsConnectionProvider>()
@@ -199,7 +201,7 @@ class CawsConnectionProvider : GatewayConnectionProvider {
                                 )
                             }
 
-                            lifetime.launch(Dispatchers.IO) {
+                            scope.launch {
                                 ApplicationManager.getApplication().messageBus.syncPublisher(WorkspaceNotifications.TOPIC)
                                     .environmentStarted(
                                         WorkspaceListStateChangeContext(
@@ -249,7 +251,7 @@ class CawsConnectionProvider : GatewayConnectionProvider {
                                     duration = timeTakenToCheckInstallation.toDouble()
                                 )
 
-                                lifetime.launch(Dispatchers.IO) {
+                                scope.launch {
                                     environmentActions.stopEnvironment()
                                     GatewayUI.getInstance().connect(parameters)
                                 }

plugins/toolkit/jetbrains-gateway/src/software/aws/toolkits/jetbrains/gateway/CawsConnectorViewPanels.kt

@@ -9,8 +9,6 @@ import com.intellij.openapi.fileChooser.FileChooserDescriptorFactory
 import com.intellij.openapi.observable.properties.PropertyGraph
 import com.intellij.openapi.rd.createNestedDisposable
 import com.intellij.openapi.rd.util.launchOnUi
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.launch
 import com.intellij.openapi.rd.util.startWithModalProgressAsync
 import com.intellij.openapi.rd.util.withUiContext
 import com.intellij.openapi.ui.DialogPanel
@@ -47,6 +45,9 @@ import com.jetbrains.gateway.welcomeScreen.MultistagePanel
 import com.jetbrains.gateway.welcomeScreen.MultistagePanelContainer
 import com.jetbrains.gateway.welcomeScreen.MultistagePanelDelegate
 import com.jetbrains.rd.util.lifetime.Lifetime
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.launch
 import software.amazon.awssdk.services.codecatalyst.CodeCatalystClient
 import software.amazon.awssdk.services.codecatalyst.model.InstanceType
 import software.aws.toolkits.core.ClientConnectionSettings
@@ -55,6 +56,7 @@ import software.aws.toolkits.core.utils.getLogger
 import software.aws.toolkits.jetbrains.core.AwsClientManager
 import software.aws.toolkits.jetbrains.core.AwsResourceCache
 import software.aws.toolkits.jetbrains.core.awsClient
+import software.aws.toolkits.jetbrains.core.coroutines.getCoroutineBgContext
 import software.aws.toolkits.jetbrains.core.credentials.AwsBearerTokenConnection
 import software.aws.toolkits.jetbrains.core.credentials.ToolkitConnectionManager
 import software.aws.toolkits.jetbrains.core.credentials.pinning.CodeCatalystConnection
@@ -473,7 +475,7 @@ class EnvironmentDetailsPanel(private val context: CawsSettings, lifetime: Lifet
                                     lifetime.launchOnUi {
                                         loadingPanel.startLoading()
                                         var panel: JComponent? = null
-                                        lifetime.launch(Dispatchers.IO) {
+                                        CoroutineScope(getCoroutineBgContext() + SupervisorJob()).launch {
                                             panel = content(project?.space)
                                         }
                                         panel?.let { wrapper.setContent(it) }