three layer model fix

MVMCoreUI/Models/Template/ThreeLayerPageTemplateModel.swift

@@ -17,7 +17,43 @@ import Foundation
 
     public var isAtomicTabs: Bool?
 
-    public var header: MoleculeStackModel?
+    public var header: MoleculeProtocol?
-    public var middle: MoleculeStackModel?
+    public var middle: MoleculeProtocol?
-    public var footer: MoleculeStackModel?
+    public var footer: MoleculeProtocol?
+    
+    public init(pageType: String, header: MoleculeProtocol?, middle: MoleculeProtocol?, footer: MoleculeProtocol?) {
+        self.pageType = pageType
+        self.header = header
+        self.middle = middle
+        self.footer = footer
+    }
+
+    enum CodingKeys: String, CodingKey {
+        case pageType
+        case screenHeading
+        case header
+        case footer
+        case middle
+        case isAtomicTabs
+    }
+
+    required public init(from decoder: Decoder) throws {
+        let typeContainer = try decoder.container(keyedBy: CodingKeys.self)
+        pageType = try typeContainer.decode(String.self, forKey: .pageType)
+        screenHeading = try typeContainer.decodeIfPresent(String.self, forKey: .screenHeading)
+        isAtomicTabs = try typeContainer.decodeIfPresent(Bool.self, forKey: .isAtomicTabs)
+        header = try typeContainer.decodeMoleculeIfPresent(codingKey: .header)
+        header = try typeContainer.decodeMoleculeIfPresent(codingKey: .middle)
+        footer = try typeContainer.decodeMoleculeIfPresent(codingKey: .footer)
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(pageType, forKey: .pageType)
+        try container.encodeIfPresent(screenHeading, forKey: .screenHeading)
+        try container.encodeIfPresent(isAtomicTabs, forKey: .isAtomicTabs)
+        try container.encodeModelIfPresent(header, forKey: .header)
+        try container.encodeModelIfPresent(header, forKey: .middle)
+        try container.encodeModelIfPresent(footer, forKey: .footer)
+    }
 }