Fix Windows docker invocation for TTS

src/services/melo-tts.ts

@@ -12,9 +12,16 @@ async function run(command: string, args: string[], stdio: "ignore" | "inherit"
     const child = spawn(command, args, {
       stdio: ["ignore", stdio, "inherit"],
       windowsHide: true,
+      shell: process.platform === "win32",
     });
 
-    child.on("error", reject);
+    child.on("error", (error) => {
+      if ((error as NodeJS.ErrnoException).code === "ENOENT" && command === "docker") {
+        reject(new Error("Docker를 찾지 못했습니다. Docker Desktop을 설치하고 실행한 뒤 다시 시도하세요."));
+        return;
+      }
+      reject(error);
+    });
     child.on("exit", (code) => {
       if (code === 0) {
         resolve();