双可执行落地：STCompiler 与 BytecodeExecutor。

- STCompiler 入口在 compiler/src/main.cpp，链 compiler+isa
- host/ 改名 executor/，BytecodeExecutor 链 vm+isa 不链 compiler
- compiler/vm 补 PUBLIC 链 isa；顶层加入 executor
- CTest：版本冒烟 2 例 + isa_roundtrip（89 断言），3/3 通过

vm/CMakeLists.txt

@@ -6,7 +6,8 @@ project(VM
         VERSION 0.1
         DESCRIPTION "寄存器虚拟机")
 
-include_directories(./include)
-
 add_library(vm STATIC
             ./src/Machine.cpp)
+
+target_include_directories(vm PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
+target_link_libraries(vm PUBLIC isa)