feat: add web server backend.

web/server/start.js

@@ -0,0 +1,40 @@
+/**
+ * start.js — safe server launcher
+ * Kills any process already on PORT before starting index.js.
+ * Run with: node web/server/start.js
+ */
+const { execSync, spawn } = require("child_process");
+const PORT = process.env.PORT || 5000;
+
+function killPort(port) {
+  try {
+    if (process.platform === "win32") {
+      const out = execSync(`netstat -ano | findstr :${port}`, { encoding: "utf-8" }).trim();
+      const pids = new Set();
+      for (const line of out.split("\n")) {
+        if (!line.includes("LISTENING")) continue;
+        const pid = line.trim().split(/\s+/).pop();
+        if (pid && pid !== "0") pids.add(pid);
+      }
+      for (const pid of pids) {
+        console.log(`[start] Killing stale process PID ${pid} on port ${port}`);
+        execSync(`taskkill /PID ${pid} /F`, { stdio: "ignore" });
+      }
+    } else {
+      execSync(`fuser -k ${port}/tcp`, { stdio: "ignore" });
+    }
+  } catch {
+    // No process on that port — fine
+  }
+}
+
+killPort(PORT);
+
+const proc = spawn(process.execPath, [require("path").join(__dirname, "index.js")], {
+  stdio: "inherit",
+  env: process.env,
+});
+
+proc.on("exit", (code) => process.exit(code ?? 0));
+process.on("SIGINT",  () => proc.kill("SIGINT"));
+process.on("SIGTERM", () => proc.kill("SIGTERM"));