refactor(include): migrate public headers to include/kcenon/container/ convention

Migrate 24 public headers from core/ to include/kcenon/container/ to match
the ecosystem convention used by all other kcenon systems. Forwarding headers
in core/ maintain backward compatibility.

Closes #439

Author: kcenon

CMakeLists.txt

@@ -279,6 +279,7 @@ set_target_properties(container_system PROPERTIES
 
 # Public include directories (for consumers of this library)
 target_include_directories(container_system PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
     $<INSTALL_INTERFACE:include>
 )
@@ -560,10 +561,12 @@ set(CONTAINER_SYSTEM_CMAKE_INSTALL_DIR "${CMAKE_INSTALL_LIBDIR}/cmake/container_
 # Canonical Include Path Configuration
 # =============================================================================
 # The canonical include path for container_system is:
-#     #include <container.h>
+#     #include <kcenon/container/container.h>   (preferred)
+#     #include <container.h>                    (legacy, via forwarding headers)
 #
 # The following directories are installed:
-#   - core/      (core container implementation)
+#   - include/kcenon/container/  (canonical public headers)
+#   - core/      (forwarding headers for backward compatibility)
 #   - internal/  (internal implementation details)
 #   - integration/ (integration adapters)
 # =============================================================================
@@ -581,6 +584,17 @@ install(TARGETS container_system
     INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
 )
 
+# Canonical public headers (kcenon ecosystem convention)
+install(DIRECTORY
+    ${CMAKE_CURRENT_SOURCE_DIR}/include/kcenon
+    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+    COMPONENT Development
+    FILES_MATCHING
+    PATTERN "*.h"
+    PATTERN "*.hpp"
+)
+
+# Backward-compatible forwarding headers and internal implementation
 install(DIRECTORY
     ${CMAKE_CURRENT_SOURCE_DIR}/core
     ${CMAKE_CURRENT_SOURCE_DIR}/internal
@@ -669,6 +683,7 @@ if(CONTAINER_BUILD_MODULES)
 
         # Include directories for module target
         target_include_directories(container_system_modules PUBLIC
+            $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
             $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
             $<INSTALL_INTERFACE:include>
         )

core/concepts.h

@@ -1,245 +1,3 @@
-/*****************************************************************************
-BSD 3-Clause License
-
-Copyright (c) 2024, kcenon
-All rights reserved.
-*****************************************************************************/
-
-/**
- * @file concepts.h
- * @brief C++20 concepts for container_system type validation.
- *
- * This header provides concepts for validating types used throughout
- * the container_system library. These concepts enable compile-time
- * validation with clear error messages, replacing SFINAE-based constraints.
- *
- * Requirements:
- * - C++20 compiler with concepts support
- * - GCC 10+, Clang 10+, MSVC 2022+
- *
- * Integration with common_system:
- * - Imports core concepts from kcenon::common::concepts
- * - Extends with container_system-specific concepts
- *
- * @see kcenon/common/concepts/concepts.h for common_system concepts
- */
-
 #pragma once
-
-#include <concepts>
-#include <type_traits>
-#include <string>
-#include <string_view>
-#include <vector>
-#include <memory>
-#include <variant>
-#include <cstdint>
-
-namespace kcenon::container {
-
-// Forward declarations
-class thread_safe_container;
-class value;
-struct array_variant;
-
-namespace concepts {
-
-/**
- * @concept Arithmetic
- * @brief A type that is arithmetic (integral or floating-point).
- *
- * Example usage:
- * @code
- * template<Arithmetic T>
- * value make_numeric_value(std::string_view name, T val);
- * @endcode
- */
-template<typename T>
-concept Arithmetic = std::is_arithmetic_v<T>;
-
-/**
- * @concept IntegralType
- * @brief A type that is an integral type.
- */
-template<typename T>
-concept IntegralType = std::integral<T>;
-
-/**
- * @concept FloatingPointType
- * @brief A type that is a floating-point type.
- */
-template<typename T>
-concept FloatingPointType = std::floating_point<T>;
-
-/**
- * @concept SignedIntegral
- * @brief A signed integral type.
- */
-template<typename T>
-concept SignedIntegral = std::signed_integral<T>;
-
-/**
- * @concept UnsignedIntegral
- * @brief An unsigned integral type.
- */
-template<typename T>
-concept UnsignedIntegral = std::unsigned_integral<T>;
-
-/**
- * @concept TriviallyCopyable
- * @brief A type that can be safely copied with memcpy.
- *
- * Use this concept for types that require SIMD-optimized operations
- * or deterministic memory layout.
- *
- * Example usage:
- * @code
- * template<TriviallyCopyable T>
- * class simd_batch { ... };  // Renamed from typed_container (Issue #328)
- * @endcode
- */
-template<typename T>
-concept TriviallyCopyable = std::is_trivially_copyable_v<T>;
-
-/**
- * @concept ValueVariantType
- * @brief A type that is valid for storage in ValueVariant.
- *
- * Valid types include:
- * - std::monostate (null)
- * - bool
- * - int16_t, uint16_t, int32_t, uint32_t, int64_t, uint64_t
- * - float, double
- * - std::string
- * - std::vector<uint8_t> (bytes)
- * - std::shared_ptr<thread_safe_container>
- * - array_variant
- *
- * Example usage:
- * @code
- * template<ValueVariantType T>
- * void set_typed(std::string_view key, T&& val);
- * @endcode
- */
-template<typename T>
-concept ValueVariantType =
-    std::same_as<std::decay_t<T>, std::monostate> ||
-    std::same_as<std::decay_t<T>, bool> ||
-    std::same_as<std::decay_t<T>, int16_t> ||
-    std::same_as<std::decay_t<T>, uint16_t> ||
-    std::same_as<std::decay_t<T>, int32_t> ||
-    std::same_as<std::decay_t<T>, uint32_t> ||
-    std::same_as<std::decay_t<T>, int64_t> ||
-    std::same_as<std::decay_t<T>, uint64_t> ||
-    std::same_as<std::decay_t<T>, float> ||
-    std::same_as<std::decay_t<T>, double> ||
-    std::same_as<std::decay_t<T>, std::string> ||
-    std::same_as<std::decay_t<T>, std::vector<uint8_t>> ||
-    std::same_as<std::decay_t<T>, std::shared_ptr<thread_safe_container>> ||
-    std::same_as<std::decay_t<T>, array_variant>;
-
-/**
- * @concept NumericValueType
- * @brief A numeric type suitable for value storage.
- *
- * Excludes bool (which has its own handling) and includes
- * all signed/unsigned integers and floating-point types.
- */
-template<typename T>
-concept NumericValueType =
-    Arithmetic<T> && !std::same_as<std::decay_t<T>, bool>;
-
-/**
- * @concept StringLike
- * @brief A type that can be converted to or used as a string.
- */
-template<typename T>
-concept StringLike =
-    std::same_as<std::decay_t<T>, std::string> ||
-    std::same_as<std::decay_t<T>, std::string_view> ||
-    std::same_as<std::decay_t<T>, const char*> ||
-    std::convertible_to<T, std::string_view>;
-
-/**
- * @concept ByteContainer
- * @brief A type that represents byte data.
- */
-template<typename T>
-concept ByteContainer =
-    std::same_as<std::decay_t<T>, std::vector<uint8_t>>;
-
-/**
- * @concept ValueVisitor
- * @brief A callable type that can visit value variants.
- *
- * Example usage:
- * @code
- * template<ValueVisitor V>
- * auto visit(V&& visitor) const;
- * @endcode
- */
-template<typename V>
-concept ValueVisitor = std::move_constructible<V>;
-
-/**
- * @concept KeyValueCallback
- * @brief A callable for key-value pair iteration.
- *
- * Example usage:
- * @code
- * template<KeyValueCallback Func>
- * void for_each(Func&& func) const;
- * @endcode
- */
-template<typename F>
-concept KeyValueCallback = std::invocable<F, const std::string&, const value&>;
-
-/**
- * @concept MutableKeyValueCallback
- * @brief A callable for mutable key-value pair iteration.
- */
-template<typename F>
-concept MutableKeyValueCallback = std::invocable<F, const std::string&, value&>;
-
-/**
- * @concept ValueMapCallback
- * @brief A callable that operates on the entire value map.
- */
-template<typename F, typename Map>
-concept ValueMapCallback = std::invocable<F, Map&>;
-
-/**
- * @concept ConstValueMapCallback
- * @brief A callable that operates on a const value map.
- */
-template<typename F, typename Map>
-concept ConstValueMapCallback = std::invocable<F, const Map&>;
-
-/**
- * @concept Serializable
- * @brief A type that provides serialization methods.
- */
-template<typename T>
-concept Serializable = requires(const T& t) {
-    { t.serialize() } -> std::convertible_to<std::vector<uint8_t>>;
-};
-
-/**
- * @concept JsonSerializable
- * @brief A type that can be serialized to JSON.
- */
-template<typename T>
-concept JsonSerializable = requires(const T& t) {
-    { t.to_json() } -> std::convertible_to<std::string>;
-};
-
-/**
- * @concept ContainerValue
- * @brief A type representing a nested container value.
- */
-template<typename T>
-concept ContainerValue =
-    std::same_as<std::decay_t<T>, std::shared_ptr<thread_safe_container>>;
-
-} // namespace concepts
-} // namespace kcenon::container
+// Forwarding header — canonical location: include/kcenon/container/concepts.h
+#include <kcenon/container/concepts.h>