fix(ffilib): runtime=True 时把 _ffilib 登记为导入模块，进入可达性扫描

Pass 0 的 _AddPending 只影响 viperbuild 的闭包 BFS，不影响 Phase1/Phase2 的 includes 可达性扫描（后者由 tr._imported_modules 驱动），所以 _ffilib 仍然没被收录、拿不到 SHA1。改为在 translate_import 里判断：若存在 runtime=True 的句柄（ViperBuild.HasRuntimeFfiHandle），则随 import ffilib 一并 NotePlainImport("_ffilib")。

App/lib/core/Gen/ImportsGenMixin.vp

@@ -11,7 +11,8 @@ import sys
 import win32.fileio as fileio
 import lib.Stub.StubMerger as StubMerger
 import lib.core.CompilerFactory as CompilerFactory
-import lib.core.Gen.Translator as HT
+import lib.core.Gen.Translator as HT
+import lib.core.builtin.ViperBuild as ViperBuild
 import lib.Stub.StubMerger.StubMergerStore as StubMergerStore
 import lib.core.VLogger as VLogger
 
@@ -589,6 +590,10 @@ novirtual class ImportsGenMixin:
                 # declare_only=1/2 is the pre-registration scan and would false-positive.
                 if trans._declare_only == 0: self._check_import_sha1(node, alias.name)
                 StubMergerStore.NotePlainImport(pool_val, ctx, alias.name, alias.asname)
+                # runtime CDLL 的 thunk 要调 _ffilib：只要存在 runtime=True 的句柄，
+                # 就把该运行时库登记成导入模块，让可达性扫描收录它并分配 SHA1。
+                if string.strcmp(alias.name, "ffilib") == 0:
+                    if ViperBuild.HasRuntimeFfiHandle() != 0: StubMergerStore.NotePlainImport(pool_val, ctx, "_ffilib", None)
         trans._imported_modules = ctx.ImportedModules
         trans._from_imports = ctx.FromImports
         return 0

App/lib/core/builtin/ViperBuild.vp

@@ -1079,6 +1079,17 @@ def IsCdlLDeclCall(node: ast.AST*) -> int:
     return _IsCDLLCall(node)
 
 
+# HasRuntimeFfiHandle - 是否存在 runtime=True 的 CDLL 句柄（决定是否要引入 _ffilib 依赖）
+def HasRuntimeFfiHandle() -> int:
+    """至少一个句柄 runtime=1 时返回 1"""
+    global _ffi_handles_rt
+    if _ffi_handles_rt is None: return 0
+    n: sizet = _ffi_handles_rt.__len__()
+    for i in range(int(n)):
+        if _ffi_handles_rt.get(i) != 0: return 1
+    return 0
+
+
 # FfiHandlePath - 查询 extern <lib> name(...) 的库路径（runtime=True 的 thunk 用它 LoadLibraryA）
 def FfiHandlePath(name: str) -> str:
     """库路径；未登记返回 None"""