Add project files

source/BreezeCore/include/breeze/Config.hpp

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+#pragma once
+
+#include <filesystem>
+#include <optional>
+#include <string>
+
+#include <nlohmann/json.hpp>
+
+/// The CLI's own, global state: where it lives and what the user configured.
+namespace breeze
+{
+
+	/// $BREEZE_HOME, or ~/.breeze. Holds config.json, the installed CLI versions (cli/), the SDK
+	/// snapshots (sdk/) and cached indexes.
+	std::filesystem::path breezeHome();
+
+	/// The keys of config.json. Each can also come from the environment (BREEZE_EDITOR,
+	/// BREEZE_SDK_SOURCE, BREEZE_CLI_SOURCE), which wins.
+	namespace config
+	{
+		inline constexpr const char* Editor = "editor";
+		inline constexpr const char* SdkSource = "sdkSource";
+		inline constexpr const char* CliSource = "cliSource";
+	}
+
+	class GlobalConfig
+	{
+	public:
+		/// Reads config.json (an absent file is an empty configuration).
+		static GlobalConfig load();
+
+		/// The environment's value for the key if set, else the file's.
+		[[nodiscard]] std::optional<std::string> effective(const std::string& key) const;
+
+		/// The file's value only.
+		[[nodiscard]] std::optional<std::string> stored(const std::string& key) const;
+
+		void set(const std::string& key, const std::string& value);
+		void erase(const std::string& key);
+		void save() const;
+
+	private:
+		nlohmann::json m_data = nlohmann::json::object();
+	};
+
+}