refactor: remove special handling for upgrade command, simplify logic

统一对所有 cloud 子命令先 ensureCsCloud 再执行，移除对 upgrade
的特殊判断，逻辑更清晰简洁。

Co-Authored-By: claude-sonnet-4-6 <noreply@anthropic.com>

src/cli/handlers/cloud.ts

@@ -253,15 +253,6 @@ export async function cloudHandler(rawArgs: string[]): Promise<void> {
 		process.exit(1)
 	}
 
-	if (args[0] === "upgrade") {
-		const bin = csCloudBin()
-		if (fs.existsSync(bin)) {
-			await runCsCloud(args)
-			return
-		}
-		await ensureCsCloud()
-		return
-	}
-
+	await ensureCsCloud()
 	await runCsCloud(args)
 }