debug(traceback): worker stderr 输出并按 fail-fast 注入 main

并行 worker 的 _vlog 不汇总；改为 stderr 直接输出 enabled/InstallSymbol；main 找不到 Install 时明确报错。

lib/core/Handles/HandlesFunctions.py

@@ -2054,12 +2054,16 @@ class FunctionHandle(BaseHandle):
             func_body = func_body[1:]
         else:
             Gen._create_doc_global(doc_symbol, None)
-        if Node.name == 'main':
+        if Node.name == 'main' and getattr(self.Trans, 'TracebackEnabled', False):
             _tb_install: str | None = getattr(self.Trans, 'TracebackInstallSymbol', None)
             if not _tb_install:
                 _tb_sha1 = getattr(Gen, 'ModuleSha1Map', {}).get('traceback')
                 if _tb_sha1:
                     _tb_install = f'{_tb_sha1}.Install'
+            if not _tb_install:
+                raise RuntimeError(
+                    '--traceback: main 入口无法解析 traceback.Install 符号'
+                    '（TracebackInstallSymbol 未设置且 ModuleSha1Map 无 traceback）')
             if _tb_install:
                 _install_fn = Gen._CreateOrReuseFuncDecl(
                     _tb_install, ir.FunctionType(ir.IntType(32), []))