replace all $ARGUMENTS (#3276)

packages/opencode/src/session/prompt.ts

@@ -1409,7 +1409,7 @@ export namespace SessionPrompt {
     const command = await Command.get(input.command)
     const agentName = command.agent ?? input.agent ?? "build"
 
-    let template = command.template.replace("$ARGUMENTS", input.arguments)
+    let template = command.template.replaceAll("$ARGUMENTS", input.arguments)
 
     const shell = ConfigMarkdown.shell(template)
     if (shell.length > 0) {