fix(agent): scope MCP manager cleanup to successful initialization

Move defer cleanup inside else block to only clean up when MCP servers
are successfully initialized. This prevents unnecessary cleanup attempts
when LoadFromMCPConfig fails.

Addresses Copilot code review feedback.

pkg/agent/loop.go

@@ -150,6 +150,16 @@ func (al *AgentLoop) Run(ctx context.Context) error {
 					"error": err.Error(),
 				})
 		} else {
+			// Ensure MCP connections are cleaned up on exit, only if initialization succeeded
+			defer func() {
+				if err := mcpManager.Close(); err != nil {
+					logger.ErrorCF("agent", "Failed to close MCP manager",
+						map[string]interface{}{
+							"error": err.Error(),
+						})
+				}
+			}()
+
 			// Register MCP tools for all agents
 			servers := mcpManager.GetServers()
 			toolCount := 0
@@ -179,16 +189,6 @@ func (al *AgentLoop) Run(ctx context.Context) error {
 					"tool_count":   toolCount,
 				})
 		}
-
-		// Ensure MCP connections are cleaned up on exit
-		defer func() {
-			if err := mcpManager.Close(); err != nil {
-				logger.ErrorCF("agent", "Failed to close MCP manager",
-					map[string]interface{}{
-						"error": err.Error(),
-					})
-			}
-		}()
 	}
 
 	for al.running.Load() {