feat: serve frontend static files from backend

artifacts/api-server/src/app.ts

@@ -2,12 +2,17 @@ import express, { type Express } from "express";
 import cors from "cors";
 import cookieParser from "cookie-parser";
 import pinoHttp from "pino-http";
+import path from "path";
+import { fileURLToPath } from "url";
 import router from "./routes";
 import openaiRouter from "./routes/openai";
 import publicRouter from "./routes/public";
 import accountsRouter from "./routes/accounts";
 import { logger } from "./lib/logger";
 
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
 const app: Express = express();
 
 app.use(
@@ -41,4 +46,17 @@ app.use("/api", router);
 app.use("/v1", openaiRouter);
 app.use("/api/v1", openaiRouter);
 
+// 提供前端靜態檔案
+const frontendDistPath = path.join(__dirname, "../../image-gen/dist");
+app.use(express.static(frontendDistPath));
+
+// SPA fallback - 所有非 API 路由都返回 index.html
+app.get("*", (req, res) => {
+  if (!req.path.startsWith("/api") && !req.path.startsWith("/v1")) {
+    res.sendFile(path.join(frontendDistPath, "index.html"));
+  } else {
+    res.status(404).json({ error: "Not found" });
+  }
+});
+
 export default app;