feat(diag): 逃逸类 LifetimeError 追加 File lifetime leak 帧，标出泄漏点

StructGenMixin: 新增 escape_leak_line——错误路径重扫被调者函数体，取指定形参的**首个逃逸点**行号；
_NoteLeak 在三处置位来源采集（字段/全局写、return 形参、传递闭包调用），新增 EscLeakWant/EscLeakLine。

Diag: DiagEntry 增加 LeakFileName/LeakLine + set_leak + emit_leak_frame（标签 File lifetime leak），
打印顺序 = 调用链 → 错误点 → 泄漏点 → 类别: 消息。

TypeGenErr.fatal_error / GenApi.fail_if_stack_addr_escape 增加 leak_file/leak_line 透传；
CallGenMixin 调用点按失败实参位取行号。**仅同模块**：跨模块 EscFuncTable 无 AST → 返回 0，不打该帧。

App/lib/core/Diag.vp

@@ -54,6 +54,10 @@ class DiagEntry:
     FrameCount: int        # 调用链帧数
     FrameFiles: sizet*     # 调用链每帧文件名（深拷贝）
     FrameLines: sizet*     # 调用链每帧行号（与 FrameFiles 同容量）
+    # 泄漏点（可选）：被调者那边**造成逃逸的写入点**。只有逃逸类 LifetimeError 会有值；
+    # 打印成独立一帧 `File lifetime leak "<file>", line N`，与调用栈帧（`File "..."`）区分。
+    LeakFileName: str
+    LeakLine: int
     Cap: int               # 内部：FrameFiles/FrameLines 容量（不参与打印）
 
 
@@ -81,6 +85,8 @@ def new_entry(max_frames: int) -> DiagEntry*:
     ent.Msg = None
     ent.Hint = None
     ent.FrameCount = 0
+    ent.LeakFileName = None
+    ent.LeakLine = 0
     ent.Cap = max_frames
     ent.FrameFiles = (sizet*)(stdlib.malloc(sizet(max_frames) * 8))
     ent.FrameLines = (sizet*)(stdlib.malloc(sizet(max_frames) * 8))
@@ -98,6 +104,8 @@ def begin(ent: DiagEntry*, category: str, msg: str, hint: str = None) -> int:
     ent.ColStart = 0
     ent.ColEnd = 0
     ent.FrameCount = 0
+    ent.LeakFileName = None
+    ent.LeakLine = 0
     return 0
 
 
@@ -111,6 +119,14 @@ def set_current(ent: DiagEntry*, file_name: str, lineno: int, col_start: int, co
     return 0
 
 
+# set_leak - 设置"泄漏点"帧（File lifetime leak）；仅逃逸类 LifetimeError 使用
+def set_leak(ent: DiagEntry*, file_name: str, lineno: int) -> int:
+    if ent is None or lineno <= 0: return 0
+    ent.LeakFileName = dup_str(file_name)
+    ent.LeakLine = lineno
+    return 0
+
+
 # add_frame - 追加调用链一帧（按"自外向内"顺序追加）
 def add_frame(ent: DiagEntry*, file_name: str, lineno: int) -> int:
     if ent is None or ent.FrameFiles is None or ent.FrameLines is None: return 0
@@ -137,6 +153,8 @@ def emit(ent: DiagEntry*, direction: int) -> int:
                 emit_frame(str(ent.FrameFiles[i_u]), int(ent.FrameLines[i_u]))
                 i_u += 1
     emit_current(ent.FileName, ent.Line, ent.ColStart, ent.ColEnd)
+    # 泄漏点帧紧跟在"错误点"之后（往下再一行），再印类别: 消息
+    if ent.LeakLine > 0: emit_leak_frame(ent.LeakFileName, ent.LeakLine)
     emit_category(ent.Category, ent.Msg)
     return 0
 
@@ -145,6 +163,7 @@ def emit(ent: DiagEntry*, direction: int) -> int:
 def free_entry(ent: DiagEntry*) -> int:
     if ent is None: return 0
     if ent.FileName is not None: stdlib.free(ent.FileName)
+    if ent.LeakFileName is not None: stdlib.free(ent.LeakFileName)
     if ent.Category is not None: stdlib.free(ent.Category)
     if ent.Msg is not None: stdlib.free(ent.Msg)
     if ent.Hint is not None: stdlib.free(ent.Hint)
@@ -222,6 +241,19 @@ def emit_frame(file_name: str, lineno: int) -> int:
     return 0
 
 
+# emit_leak_frame - "泄漏点"帧：标签用 `File lifetime leak`，与调用栈帧（`File "..."`）区分
+def emit_leak_frame(file_name: str, lineno: int) -> int:
+    if file_name is None: return 0
+    if lineno > 0:
+        stdio.printf('  File lifetime leak "%s", line %d\n', file_name, lineno)
+        src: str = read_source_line(file_name, lineno)
+        if src is not None:
+            stdio.printf("    %s\n", src)
+            stdlib.free(src)
+    else: stdio.printf('  File lifetime leak "%s"\n', file_name)
+    return 0
+
+
 # emit_current - 当前帧（带 caret 列范围；行读不出时印警告）
 def emit_current(file_name: str, lineno: int, col_start: int, col_end: int) -> int:
     # Sanity defense: read the line first to verify lineno belongs to the current file.