Steps 297-302: Phase 11b complete + Phase 11c step 302 (68/68 tests)

Phase 11b — Validation & Conflict Completion:
- Step 297: Subject 2-4 validation rules E0600-E0805 (12/12)
- Step 298: Subject 5-8 validation rules E0900-E1202 (12/12)
- Step 299: Cross-type conflict detection, 6 conflict pairs (12/12)
- Step 300: TransformEngineExtended — float folding, dead var, annotation-aware (12/12)
- Step 301: Phase 11b integration tests (8/8)

Phase 11c — Parser Deepening (start):
- Step 302: New AST nodes — ClassDeclaration, InterfaceDeclaration,
  MethodDeclaration, GenericType, TypeParameter with JSON roundtrip (12/12)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

editor/src/ast/ClassDeclaration.h

@@ -0,0 +1,53 @@
+#pragma once
+#include "ASTNode.h"
+#include "Function.h"
+#include <string>
+#include <vector>
+
+// ClassDeclaration — represents a class/struct definition
+class ClassDeclaration : public ASTNode {
+public:
+    std::string name;
+    std::string superClass;     // base class name, empty if none
+    bool isAbstract = false;
+
+    ClassDeclaration() { conceptType = "ClassDeclaration"; }
+    ClassDeclaration(const std::string& id_, const std::string& name_)
+        : name(name_) {
+        this->id = id_;
+        this->conceptType = "ClassDeclaration";
+    }
+    // Children roles: "interfaces" (list of CustomType), "fields" (list of Variable),
+    //                 "methods" (list of MethodDeclaration), "annotations"
+};
+
+// InterfaceDeclaration — represents an interface/trait/protocol
+class InterfaceDeclaration : public ASTNode {
+public:
+    std::string name;
+
+    InterfaceDeclaration() { conceptType = "InterfaceDeclaration"; }
+    InterfaceDeclaration(const std::string& id_, const std::string& name_)
+        : name(name_) {
+        this->id = id_;
+        this->conceptType = "InterfaceDeclaration";
+    }
+    // Children roles: "methods" (list of MethodDeclaration), "annotations"
+};
+
+// MethodDeclaration — extends Function with class-specific fields
+class MethodDeclaration : public Function {
+public:
+    std::string className;
+    bool isStatic = false;
+    std::string visibility = "public";  // "public", "private", "protected"
+    bool isOverride = false;
+    bool isVirtual = false;
+
+    MethodDeclaration() { conceptType = "MethodDeclaration"; }
+    MethodDeclaration(const std::string& id_, const std::string& name_)
+        : Function(id_, name_) {
+        this->conceptType = "MethodDeclaration";
+    }
+    // Inherits children: "parameters", "body", "returnType", "annotations"
+};

editor/src/ast/GenericType.h

@@ -0,0 +1,31 @@
+#pragma once
+#include "ASTNode.h"
+#include <string>
+
+// GenericType — a parameterized type like List<T> or Map<K, V>
+class GenericType : public ASTNode {
+public:
+    std::string baseName;  // e.g. "List", "Map", "Optional"
+
+    GenericType() { conceptType = "GenericType"; }
+    GenericType(const std::string& id_, const std::string& base)
+        : baseName(base) {
+        this->id = id_;
+        this->conceptType = "GenericType";
+    }
+    // Children roles: "typeParameters" (list of TypeParameter or PrimitiveType)
+};
+
+// TypeParameter — a type variable like T, K, V with optional constraint
+class TypeParameter : public ASTNode {
+public:
+    std::string name;       // e.g. "T", "K"
+    std::string constraint; // e.g. "Comparable", empty if unconstrained
+
+    TypeParameter() { conceptType = "TypeParameter"; }
+    TypeParameter(const std::string& id_, const std::string& name_)
+        : name(name_) {
+        this->id = id_;
+        this->conceptType = "TypeParameter";
+    }
+};