fix(vpi): 注入模块级全局变量 external declare，修复跨模块 stub 误杀

vpi 注入原只处理函数 declare 与 CTypedef，普通模块级全局变量
（tokens.vp 的 _op_head: OpEntry | t.CPtr）不创建 GlobalVariable，
lexer.vp from-import 读取时 find_global_in_module 找不到 →
"跨模块全局变量类型未知（stub 未注入）"。新增
_inject_global_variable_declare：解析注解类型（裸类→Ptr、CArray→
元素指针），创建短名 external global（COFF 按名链接），接入 AnnAssign
分支（非 CTypedef 走全局变量注入）。

App/lib/StubGen/VpiReader.vp

@@ -916,13 +916,18 @@ def _ParseVpiIntoModuleImpl(pool: memhub.MemBuddy | t.CPtr,
                                      funcs_ptr, max_funcs)
             continue
 
-        # AnnAssign with t.CTypedef → 注册 CTypedef
+        # AnnAssign with t.CTypedef → 注册 CTypedef；
+        # 普通模块级全局变量（如 tokens._op_head）→ external global declare
         if kd == ast.ASTKind.AnnAssign:
             aa: ast.AnnAssign | t.CPtr = (ast.AnnAssign | t.CPtr)(child)
             if aa is None:
                 continue
             if HandlesType._is_ctypedef_annotation(aa.annotation) != 0:
                 _register_ctypedef_from_annassign(pool, aa)
+            else:
+                _inject_global_variable_declare(pool, mod, aa, trans,
+                                                stub_imported_modules, stub_from_imports,
+                                                i32_ty, i8_ptr_ty)
             continue
 
         # ClassDef → 递归注入类内方法（如 MemBuddy.__init__/alloc）
@@ -972,6 +977,62 @@ def _ParseVpiIntoModuleImpl(pool: memhub.MemBuddy | t.CPtr,
     return 1
 
 
+# ============================================================
+# _inject_global_variable_declare - 从 vpi AnnAssign 创建模块级全局变量 declare
+#
+# 背景：vpi 里模块级全局变量（如 tokens.vp 的 _op_head: OpEntry | t.CPtr = None）
+# 需在当前模块创建 external global 声明（短名 @name，COFF 按名链接），否则
+# 跨模块 from-import 读取全局变量时 find_global_in_module 找不到 →
+# "跨模块全局变量类型未知（stub 未注入）" 误杀（lexer.vp 读 tokens._op_head）。
+# ============================================================
+def _inject_global_variable_declare(pool: memhub.MemBuddy | t.CPtr,
+                                    mod: llvmlite.LLVMModule | t.CPtr,
+                                    aa: ast.AnnAssign | t.CPtr,
+                                    trans: HT.Translator | t.CPtr,
+                                    imported_modules: str,
+                                    from_imports: str,
+                                    i32_ty: llvmlite.LLVMType | t.CPtr,
+                                    i8_ptr_ty: llvmlite.LLVMType | t.CPtr) -> None:
+    """从 vpi AnnAssign 创建模块级全局变量 external declare（短名 @name）"""
+    if pool is None or mod is None or aa is None or trans is None:
+        return
+    tgt_v: ast.AST | t.CPtr = aa.target
+    if tgt_v is None or tgt_v.kind() != ast.ASTKind.Name:
+        return
+    nm_v: ast.Name | t.CPtr = (ast.Name | t.CPtr)(tgt_v)
+    if nm_v is None or nm_v.id is None:
+        return
+    gname_v: str = nm_v.id
+    if gname_v[0] == '\0':
+        return
+    # 去重：遍历模块全局变量链表（短名匹配）
+    cur_v: llvmlite.GlobalVariable | t.CPtr = mod.GlobalHead
+    while cur_v is not None:
+        if cur_v.Name is not None and string.strcmp(cur_v.Name, gname_v) == 0:
+            return
+        cur_v = cur_v.Next
+    # 解析注解类型（裸类 → Ptr(struct)，CArray → 元素指针）
+    resolved_v: llvmlite.LLVMType | t.CPtr = None
+    if aa.annotation is not None:
+        resolved_v = HandlesType.resolve_annotation_type(
+            pool, aa.annotation, imported_modules, from_imports, trans)
+    if resolved_v is None:
+        return  # 类型解析失败跳过：调用侧有 fail-fast 定位
+    gv_ty_v: llvmlite.LLVMType | t.CPtr = resolved_v
+    match resolved_v:
+        case llvmlite.LLVMType.Struct(_, _, _):
+            gv_ty_v = llvmlite.Ptr(pool, resolved_v)
+        case llvmlite.LLVMType.Array(aelem_v, _):
+            gv_ty_v = llvmlite.Ptr(pool, aelem_v)
+        case _:
+            gv_ty_v = resolved_v
+    gv_v: llvmlite.GlobalVariable | t.CPtr = llvmlite.new_global_variable(pool, gname_v, gv_ty_v)
+    if gv_v is None:
+        return
+    llvmlite.module_add_global(mod, gv_v)
+    gv_v.Linkage = "external"
+
+
 # ============================================================
 # _inject_function_declare - 为单个 FunctionDef 创建 declare 声明
 #