Add platform arg to run container options

Co-authored-by: bwateratmsft <36966225+bwateratmsft@users.noreply.github.com>

Author: Copilot

packages/vscode-container-client/src/clients/DockerClientBase/DockerClientBase.ts

@@ -695,11 +695,12 @@ export abstract class DockerClientBase extends ConfigurableClient implements ICo
             withDockerAddHostArg(options.addHost),
             withDockerMountsArg(options.mounts),
             withDockerLabelsArg(options.labels),
-            withDockerEnvArg(options.environmentVariables),
-            withNamedArg('--env-file', options.environmentFiles),
-            withNamedArg('--entrypoint', options.entrypoint),
-            withDockerExposePortsArg(options.exposePorts),
-            withVerbatimArg(options.customOptions),
+            withDockerEnvArg(options.environmentVariables),
+            withNamedArg('--env-file', options.environmentFiles),
+            withNamedArg('--entrypoint', options.entrypoint),
+            withDockerExposePortsArg(options.exposePorts),
+            withDockerPlatformArg(options.platform),
+            withVerbatimArg(options.customOptions),
             withArg(options.imageRef),
             typeof options.command === 'string' ? withVerbatimArg(options.command) : withArg(...(toArray(options.command || []))),
         )();

packages/vscode-container-client/src/contracts/ContainerClient.ts

@@ -745,6 +745,10 @@ export type RunContainerCommandOptions = CommonCommandOptions & {
      * Optional expose ports for the container
      */
     exposePorts?: Array<number>;
+    /**
+     * Target platform for the container
+     */
+    platform?: ContainerPlatform;
     /**
      * Additional custom options to pass
      */

packages/vscode-container-client/src/test/DockerClient.test.ts

@@ -197,4 +197,33 @@ describe('DockerClient (unit)', () => {
         expect(pwshQuoted).to.deep.equal(['container', 'run', 'someimage', 'sh', '-c', 'echo` hello` world']);
         expect(bashQuoted).to.deep.equal(['container', 'run', 'someimage', 'sh', '-c', 'echo\\ hello\\ world']);
     });
+
+    it('Should include platform flag when platform is specified', async () => {
+        const options: RunContainerCommandOptions = {
+            imageRef: 'someimage',
+            platform: {
+                os: 'linux',
+                architecture: 'arm64'
+            },
+        };
+
+        const commandResponse = await client.runContainer(options);
+        const args = commandResponse.args;
+
+        // Find the position of --platform flag
+        const platformFlagIndex = args.findIndex(arg => 
+            typeof arg === 'string' ? arg === '--platform' : arg.value === '--platform'
+        );
+        
+        // Verify that --platform flag is present
+        expect(platformFlagIndex).to.be.greaterThan(-1);
+        
+        // Verify that the value after --platform matches our expected platform
+        const platformValue = args[platformFlagIndex + 1];
+        const platformValueStr = typeof platformValue === 'string' 
+            ? platformValue 
+            : platformValue.value;
+        
+        expect(platformValueStr).to.equal('linux/arm64');
+    });
 });