chore: add proper-lockfile for safe database read/write operations and implement retry logic for file access

src/lib/9remoteManager.js

@@ -0,0 +1,35 @@
+// 9remote process lifecycle manager
+let remoteProcess = null;
+
+export function setRemoteProcess(child) {
+  remoteProcess = child;
+}
+
+export function getRemoteProcess() {
+  return remoteProcess;
+}
+
+export function killRemote() {
+  if (!remoteProcess) return;
+  
+  try {
+    remoteProcess.kill("SIGTERM");
+    console.log(`[9remote] Killed process ${remoteProcess.pid}`);
+    remoteProcess = null;
+  } catch (err) {
+    console.log(`[9remote] Failed to kill:`, err.message);
+    remoteProcess = null;
+  }
+}
+
+// Register cleanup handlers
+if (typeof process !== "undefined") {
+  const cleanup = () => {
+    killRemote();
+    process.exit(0);
+  };
+
+  process.on("SIGTERM", cleanup);
+  process.on("SIGINT", cleanup);
+  process.on("beforeExit", killRemote);
+}