fix(flow): 函数体入口清空 break/continue 目标与 match-case 标记

- FuncGenDef.translate_function_def：进函数体前保存并清空 _break_bb / _continue_bb /
  _in_match_case，退出恢复
- FuncGenMixin：嵌套函数体与 lambda 体两处同样处理——原实现下嵌套函数体内的
  break/continue 会继承外层函数的跳转目标（跨函数 br，非法 IR）

App/lib/core/Gen/Func/FuncGenDef.vp

@@ -892,10 +892,18 @@ novirtual class FuncGenDef(CallGenBase.CallGenBase):
         # 返回注解上下文（[C①] 裸名泛型构造的类型实参回退来源之一）：
         # 进入函数体前记录本函数返回注解，退出时恢复外层函数的值
         old_ret_annot: ast.AST* = trans.CurFuncRetAnnot
+        # break/continue 目标与 match-case 标记：新函数作用域必须清空（见下方赋值），
+        # 否则嵌套函数体内的 break/continue 会继承外层函数（甚至跨函数）的 br 目标
+        old_break_bb: rawptr[llvmlite.BasicBlock] = trans._break_bb
+        old_continue_bb: rawptr[llvmlite.BasicBlock] = trans._continue_bb
+        old_inmc: int = trans._in_match_case
 
         trans._cur_func = func
         trans._cur_builder = func_builder
         trans.CurFuncRetAnnot = fd.returns
+        trans._break_bb = None
+        trans._continue_bb = None
+        trans._in_match_case = 0
         # 清空 global/nonlocal 名称集合（新函数作用域）
         GenApi.clear_scope_names(trans)
         # 重置链内 nonlocal 堆预建标志（每函数只建一次；多嵌套函数定义
@@ -1040,6 +1048,9 @@ novirtual class FuncGenDef(CallGenBase.CallGenBase):
         self.Gen.VarGen.exit_scope(trans.SymTab)
         trans._cur_func = old_func
         trans._cur_builder = old_builder
+        trans._break_bb = old_break_bb
+        trans._continue_bb = old_continue_bb
+        trans._in_match_case = old_inmc
         trans._global_name_count = old_global_count
         trans._nonlocal_name_count = old_nonlocal_count
         trans._closure_env_count = old_env_count

App/lib/core/Gen/Func/FuncGenMixin.vp

@@ -181,6 +181,11 @@ novirtual class FuncGenMixin(CallGenBase.CallGenBase):
         old_global_count: int = trans._global_name_count
         old_nonlocal_count: int = trans._nonlocal_name_count
         old_env_count: int = trans._closure_env_count
+        # break/continue 目标与 match-case 标记：新函数作用域必须清空（见下方赋值），
+        # 否则嵌套函数体内的 break/continue 会继承外层函数的跳转目标（跨函数 br）
+        old_break_bb: rawptr[llvmlite.BasicBlock] = trans._break_bb
+        old_continue_bb: rawptr[llvmlite.BasicBlock] = trans._continue_bb
+        old_inmc: int = trans._in_match_case
         # nonlocal 集合独立缓冲：嵌套函数注册 nonlocal 写入共享缓冲 [0] 会
         # 覆盖父函数集合（ClosureTest2 Test 7 不同变量场景：level2 的 b 覆盖
         # level1 的 a → level1 env[0] 存错）。嵌套函数用独立缓冲，翻译完恢复。
@@ -192,6 +197,9 @@ novirtual class FuncGenMixin(CallGenBase.CallGenBase):
         trans._cur_builder = func_builder
         trans._cur_func_name = func_name
         GenApi.clear_scope_names(trans)
+        trans._break_bb = None
+        trans._continue_bb = None
+        trans._in_match_case = 0
         # 嵌套函数独立 nonlocal 缓冲（避免覆盖父函数集合）
         trans._nonlocal_names = stdlib.malloc(HT.MAX_GLOBAL_NAMES * 8)
         trans._nonlocal_types = stdlib.malloc(HT.MAX_GLOBAL_NAMES * 8)
@@ -254,6 +262,9 @@ novirtual class FuncGenMixin(CallGenBase.CallGenBase):
         self.Gen.VarGen.exit_scope(trans.SymTab)
         trans._cur_func = old_func
         trans._cur_builder = old_builder
+        trans._break_bb = old_break_bb
+        trans._continue_bb = old_continue_bb
+        trans._in_match_case = old_inmc
         if dbg_pushed_n != 0:
             DebugInfoGen.PopFunction(func_builder)
         # NOTE: _nonlocal_names 和 _nonlocal_name_count 仍为嵌套函数的值
@@ -1148,10 +1159,18 @@ novirtual class FuncGenMixin(CallGenBase.CallGenBase):
         old_global_count: int = trans._global_name_count
         old_nonlocal_count: int = trans._nonlocal_name_count
         old_env_count: int = trans._closure_env_count
+        # break/continue 目标与 match-case 标记：新函数作用域必须清空（见下方赋值），
+        # 否则 lambda 体内的 break/continue 会继承外层函数的跳转目标（跨函数 br）
+        old_break_bb: rawptr[llvmlite.BasicBlock] = trans._break_bb
+        old_continue_bb: rawptr[llvmlite.BasicBlock] = trans._continue_bb
+        old_inmc: int = trans._in_match_case
         trans._cur_func = func
         trans._cur_builder = func_builder
         trans._cur_func_name = mangled_promoted
         GenApi.clear_scope_names(trans)
+        trans._break_bb = None
+        trans._continue_bb = None
+        trans._in_match_case = 0
 
         # 9. 捕获变量：从 env 堆槽加载值到局部 alloca
         for ci in range(cap_count):
@@ -1216,6 +1235,9 @@ novirtual class FuncGenMixin(CallGenBase.CallGenBase):
         self.Gen.VarGen.exit_scope(trans.SymTab)
         trans._cur_func = old_func
         trans._cur_builder = old_builder
+        trans._break_bb = old_break_bb
+        trans._continue_bb = old_continue_bb
+        trans._in_match_case = old_inmc
         trans._cur_func_name = old_func_name
         trans._global_name_count = old_global_count
         trans._nonlocal_name_count = old_nonlocal_count