feat(rust): split core library into activate/license/heartbeat modules with build.rs and C ABI tests

native/craft-core/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "craft-core"
+version = "1.0.0"
+edition = "2021"
+description = "CraftLabs 授权核心库 — Rust 实现，导出 craft_* C ABI。目标平台：Linux（主）> Windows（次）> macOS（最低）"
+
+[lib]
+crate-type = ["cdylib", "staticlib"]
+name = "craftlabs_auth_bitanswer"
+
+[dependencies]
+obfstr = "0.4"
+sha2 = "0.10"
+
+[target.'cfg(target_os = "windows")'.dependencies]
+windows-sys = { version = "0.52", features = ["Win32_System_Diagnostics_Debug"], optional = true }
+
+[build-dependencies]
+sha2 = "0.10"
+
+[features]
+default = ["security-hardening"]
+security-hardening = []