feat(tpv): Spec 注解侧填符号性（SpecWithSign + 变量/字段接入）

- TypeSpec 新增 SpecWithSign：整数 TS_INT↔TS_UINT 切换 + 驻留（SpecToText 键区分符号）
- set_var_annot_class_name 接入：注解类名提取符号性，补 Spec 无符号性
- add_field 接入：字段注解类名提取符号性，补 Spec 无符号性

App/lib/core/Gen/StructGenMixin.vp

@@ -407,6 +407,12 @@ class StructGenMixin:
         arena_f: TSpec.TypeSpecArena | t.CPtr = self.Gen.TypeGenBase.ensure_spec_arena()
         if arena_f is not None:
             fe.Spec = TSpec.SpecFromLLVMType(arena_f, field_ty)
+            # [S4 注解侧填 Spec] 补字段 Spec 整数符号性（annot_class_name 携带
+            # 真实无符号性；LLVM 反推恒 TS_INT）
+            if fe.Spec is not None and annot_class_name is not None:
+                sign_f: int = self.Gen.TypeGenCType.spec_sign_of_annot(annot_class_name)
+                if sign_f != TSpec.TS_SIGN_UNKNOWN:
+                    fe.Spec = TSpec.SpecWithSign(arena_f, fe.Spec, sign_f)
 
         struct_entry.FieldCount = idx + 1
         return idx

App/lib/core/Gen/Type/TypeSpec.vp

@@ -817,6 +817,56 @@ def SpecPointedTo(sp: TypeSpec | t.CPtr) -> TypeSpec | t.CPtr:
     return sp.Elem
 
 
+# ============================================================
+# SpecWithSign - 复制 Spec 并按注解覆盖整数符号性（TS_INT ↔ TS_UINT）
+#
+# 背景（S4 注解侧填 Spec）：SpecFromLLVMType 从 LLVM 类型反推时，整数恒
+# TS_INT（LLVM iN 不分符号）。但 SpecToText 对 TS_INT 编 "i%d"、TS_UINT 编
+# "u%d"，符号性由 **Kind** 区分 —— 若只改 IsSigned 不改 Kind，两个符号性不同
+# 的整数会得到相同驻留键 "i%d" 而撞键（同键不同义，返回错误实例）。
+# 注解侧知道真实符号性（uint32 等无符号名），须把 TS_INT 切为 TS_UINT。
+#
+# 浅拷贝结构（Elem/Ret/Params 指针共享已驻留子实例）；仅当符号性实际变化才
+# 复制并驻留，否则返回原实例。驻留去重 ⇒ 同「结构+符号」共享一份。
+# ============================================================
+def SpecWithSign(arena: TypeSpecArena | t.CPtr,
+                 sp: TypeSpec | t.CPtr,
+                 is_signed: int) -> TypeSpec | t.CPtr:
+    """复制 sp 并覆盖整数符号性，驻留后返回；无变化返回原实例，失败返回 None"""
+    if sp is None:
+        return None
+    new_kind: int = sp.Kind
+    new_signed: int = sp.IsSigned
+    if is_signed == TS_SIGN_UNSIGNED and sp.Kind == TS_INT:
+        new_kind = TS_UINT
+        new_signed = TS_SIGN_UNSIGNED
+    elif is_signed == TS_SIGN_SIGNED and sp.Kind == TS_UINT:
+        new_kind = TS_INT
+        new_signed = TS_SIGN_SIGNED
+    if new_kind == sp.Kind:
+        return sp
+    cp: TypeSpec | t.CPtr = _spec_alloc()
+    if cp is None:
+        return None
+    cp.Kind = new_kind
+    cp.Bits = sp.Bits
+    cp.IsSigned = new_signed
+    cp.PtrLevel = sp.PtrLevel
+    cp.Elem = sp.Elem
+    cp.ArrayCount = sp.ArrayCount
+    cp.BaseName = sp.BaseName
+    cp.Ret = sp.Ret
+    cp.Params = sp.Params
+    cp.ParamCount = sp.ParamCount
+    cp.IsVarArg = sp.IsVarArg
+    cp.Storage = sp.Storage
+    cp.ElemBits = sp.ElemBits
+    cp.IsElemPtr = sp.IsElemPtr
+    cp.DerefBase = sp.DerefBase
+    cp.Ty = sp.Ty
+    return InternSpec(arena, cp)
+
+
 def SpecIsUnsigned(sp: TypeSpec | t.CPtr) -> int:
     """是否无符号整数（单一真源；未知返回 0）"""
     if sp is None:

App/lib/core/Gen/VarGenMixin.vp

@@ -129,6 +129,15 @@ class VarGenMixin:
         if entry is None:
             return 1
         entry.AnnotClassName = class_name
+        # [S4 注解侧填 Spec] 补 Spec 整数符号性：SpecFromLLVMType 反推恒 TS_INT
+        # （LLVM iN 不分符号），注解类名携带真实无符号性（uint32/CUInt32T 等）。
+        # 切 TS_INT→TS_UINT 供后续消费者切读（逐步替代 AnnotClassName 的符号性判断）。
+        if entry.Spec is not None and class_name is not None:
+            sign: int = self.Gen.TypeGenCType.spec_sign_of_annot(class_name)
+            if sign != TSpec.TS_SIGN_UNKNOWN:
+                arena_sn: TSpec.TypeSpecArena | t.CPtr = self.Gen.TypeGenBase.ensure_spec_arena()
+                if arena_sn is not None:
+                    entry.Spec = TSpec.SpecWithSign(arena_sn, entry.Spec, sign)
         return 0
 
     # ============================================================