Attempted fixes

includes/plugins/sdk.js

@@ -54,6 +54,22 @@ const sodium = require('sodium-native');
  */
 const pluginRegistry = new Map();
 
+// Serialize HyperDB insert/delete/flush per plugin (HyperDB refuses flush while mutating)
+const dbWriteQueues = new Map();
+
+/**
+ * Run a write operation after prior writes for the same plugin complete.
+ * @param {string} pluginDomain
+ * @param {Function} fn
+ * @returns {Promise<*>}
+ */
+function enqueueDbWrite(pluginDomain, fn) {
+  const prev = dbWriteQueues.get(pluginDomain) || Promise.resolve();
+  const next = prev.then(() => fn(), () => fn());
+  dbWriteQueues.set(pluginDomain, next.catch(() => {}));
+  return next;
+}
+
 // Current active plugin domain (for request handling)
 let activePluginDomain = null;
 
@@ -3940,9 +3956,18 @@ const sdk = {
      * @returns {Promise<void>}
      */
     async insert(collection, doc) {
+      const pluginDomain = _getPluginDomain();
+      if (!pluginDomain) {
+        logError('PluginSDK', `[db.insert] Plugin domain not available`);
+        throw new Error('Plugin domain not available');
+      }
+      return enqueueDbWrite(pluginDomain, () => this._insert(collection, doc));
+    },
+
+    async _insert(collection, doc) {
       const startTime = Date.now();
       logDebug('PluginSDK', `[db.insert] Starting insert to ${collection}`);
-      
+
       const pluginDomain = _getPluginDomain();
       if (!pluginDomain) {
         logError('PluginSDK', `[db.insert] Plugin domain not available`);
@@ -4103,6 +4128,14 @@ const sdk = {
      * @returns {Promise<void>}
      */
     async delete(collection, query) {
+      const pluginDomain = _getPluginDomain();
+      if (!pluginDomain) {
+        throw new Error('Plugin domain not available');
+      }
+      return enqueueDbWrite(pluginDomain, () => this._delete(collection, query));
+    },
+
+    async _delete(collection, query) {
       const db = this._getDatabase();
       if (!db) {
         throw new Error('Database not initialized for this plugin');
@@ -4115,9 +4148,18 @@ const sdk = {
      * @returns {Promise<void>}
      */
     async flush() {
+      const pluginDomain = _getPluginDomain();
+      if (!pluginDomain) {
+        logError('PluginSDK', `[db.flush] Plugin domain not available`);
+        throw new Error('Plugin domain not available');
+      }
+      return enqueueDbWrite(pluginDomain, () => this._flush());
+    },
+
+    async _flush() {
       const startTime = Date.now();
       logDebug('PluginSDK', `[db.flush] Starting flush`);
-      
+
       const pluginDomain = _getPluginDomain();
       if (!pluginDomain) {
         logError('PluginSDK', `[db.flush] Plugin domain not available`);