fix(core): Address code review feedback - improve error handling and documentation

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

packages/core/examples/enhanced-kernel-example.ts

@@ -174,7 +174,7 @@ async function setupServiceFactories(kernel: EnhancedObjectKernel) {
   kernel.registerServiceFactory(
     'request-id',
     () => {
-      return `req-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
+      return `req-${Date.now()}-${Math.random().toString(36).slice(2, 11)}`;
     },
     ServiceLifecycle.TRANSIENT
   );

packages/core/src/enhanced-kernel.test.ts

@@ -145,7 +145,7 @@ describe('EnhancedObjectKernel', () => {
             await expect(async () => {
                 await kernel.bootstrap();
             }).rejects.toThrow('timeout');
-        }, 10000);
+        }, 1000); // Test should complete in 1 second
 
         it('should timeout plugin start if it takes too long', async () => {
             const plugin: PluginMetadata = {
@@ -163,7 +163,7 @@ describe('EnhancedObjectKernel', () => {
             await expect(async () => {
                 await kernel.bootstrap();
             }).rejects.toThrow();
-        }, 10000);
+        }, 1000); // Test should complete in 1 second
 
         it('should complete plugin startup within timeout', async () => {
             const plugin: PluginMetadata = {

packages/core/src/enhanced-kernel.ts

@@ -462,18 +462,28 @@ export class EnhancedObjectKernel {
 
     private registerShutdownSignals(): void {
         const signals: NodeJS.Signals[] = ['SIGINT', 'SIGTERM', 'SIGQUIT'];
+        let shutdownInProgress = false;
+        
+        const handleShutdown = async (signal: string) => {
+            if (shutdownInProgress) {
+                this.logger.warn(`Shutdown already in progress, ignoring ${signal}`);
+                return;
+            }
+            
+            shutdownInProgress = true;
+            this.logger.info(`Received ${signal} - initiating graceful shutdown`);
+            
+            try {
+                await this.shutdown();
+                process.exit(0);
+            } catch (error) {
+                this.logger.error('Shutdown failed', error as Error);
+                process.exit(1);
+            }
+        };
 
         for (const signal of signals) {
-            process.on(signal, async () => {
-                this.logger.info(`Received ${signal} - initiating graceful shutdown`);
-                try {
-                    await this.shutdown();
-                    process.exit(0);
-                } catch (error) {
-                    this.logger.error('Shutdown failed', error as Error);
-                    process.exit(1);
-                }
-            });
+            process.on(signal, () => handleShutdown(signal));
         }
     }
 

packages/core/src/plugin-loader.ts

@@ -228,6 +228,8 @@ export class PluginLoader {
 
     /**
      * Detect circular dependencies in service factories
+     * Note: This only detects cycles in service dependencies, not plugin dependencies.
+     * Plugin dependency cycles are detected in the kernel's resolveDependencies method.
      */
     detectCircularDependencies(): string[] {
         const cycles: string[] = [];
@@ -369,24 +371,23 @@ export class PluginLoader {
             return;
         }
 
-        // Configuration validation would happen here
-        // For now, just log that schema is present
-        this.logger.debug(`Plugin ${plugin.name} has configuration schema`);
+        // TODO: Configuration validation implementation
+        // This requires plugin config to be passed during loading
+        // For now, just validate that the schema exists
+        this.logger.debug(`Plugin ${plugin.name} has configuration schema (validation not yet implemented)`);
     }
 
     private async verifyPluginSignature(plugin: PluginMetadata): Promise<void> {
         if (!plugin.signature) {
             return;
         }
 
-        // Signature verification would happen here
-        // This is a placeholder for security implementation
-        this.logger.debug(`Plugin ${plugin.name} signature verification (placeholder)`);
-        
+        // TODO: Plugin signature verification implementation
         // In a real implementation:
         // 1. Extract public key from trusted source
         // 2. Verify signature against plugin code hash
         // 3. Throw error if verification fails
+        this.logger.debug(`Plugin ${plugin.name} signature verification (not yet implemented)`);
     }
 
     private async getSingletonService<T>(registration: ServiceRegistration): Promise<T> {