Auto-detect Python launcher on Windows

src/python-runtime.ts

@@ -1,3 +1,4 @@
+import { spawn } from "node:child_process";
 import { constants as fsConstants } from "node:fs";
 import { access } from "node:fs/promises";
 import path from "node:path";
@@ -10,6 +11,23 @@ function splitCommand(command: string): string[] {
   return parts.map((part) => part.replace(/^"(.*)"$/, "$1"));
 }
 
+async function canRun(command: string, args: string[]): Promise<boolean> {
+  return await new Promise<boolean>((resolve) => {
+    const child = spawn(command, [...args, "--version"], {
+      stdio: ["ignore", "ignore", "ignore"],
+      windowsHide: true,
+    });
+
+    child.on("error", () => {
+      resolve(false);
+    });
+
+    child.on("exit", (code) => {
+      resolve(code === 0);
+    });
+  });
+}
+
 async function fileExists(target: string): Promise<boolean> {
   try {
     await access(target, fsConstants.X_OK);
@@ -39,10 +57,35 @@ export async function resolveBasePythonCommand(config: AppConfig): Promise<{ com
   }
 
   if (process.platform === "win32") {
-    return { command: "python", args: [] };
+    const candidates = [
+      { command: "python", args: [] as string[] },
+      { command: "py", args: ["-3"] },
+      { command: "py", args: [] as string[] },
+    ];
+
+    for (const candidate of candidates) {
+      if (await canRun(candidate.command, candidate.args)) {
+        return candidate;
+      }
+    }
+
+    throw new Error(
+      "Windows에서 사용할 Python 실행기를 찾지 못했습니다. `python --version` 또는 `py -3 --version` 이 먼저 동작해야 합니다. 필요하면 .env 에 LOCAL_AI_PYTHON=python 또는 LOCAL_AI_PYTHON=py -3 를 넣으세요.",
+    );
   }
 
-  return { command: "python3", args: [] };
+  const unixCandidates = [
+    { command: "python3", args: [] as string[] },
+    { command: "python", args: [] as string[] },
+  ];
+
+  for (const candidate of unixCandidates) {
+    if (await canRun(candidate.command, candidate.args)) {
+      return candidate;
+    }
+  }
+
+  throw new Error("사용 가능한 Python 실행기를 찾지 못했습니다. `python3 --version` 또는 `python --version` 이 먼저 동작해야 합니다.");
 }
 
 export async function resolveWorkerPythonCommand(config: AppConfig): Promise<{ command: string; args: string[] }> {