fix: 清除错误默认模型与端口硬编码，文档机器路径占位符化

tests/e2e/test_pipeline.py

@@ -1,7 +1,7 @@
 """E2E Tests for COBOL->Java Verification Platform
 
 Run: cd <project-root> && python -m pytest tests/e2e/ -v
-Requires: web server on http://127.0.0.1:8000, WSL available,
+Requires: web server on http://127.0.0.1:$TEST_PORT, WSL available,
           DEEPSEEK_API_KEY set in the environment.
 """
 import json, os, sys, time, uuid, shutil
@@ -11,7 +11,8 @@ from pathlib import Path
 import pytest
 
 PROJECT = Path(__file__).parent.parent.parent.resolve()
-BASE_URL = "http://127.0.0.1:8000"
+TEST_PORT = int(os.environ.get("TEST_PORT", "8000"))
+BASE_URL = f"http://127.0.0.1:{TEST_PORT}"
 TASKS_DIR = PROJECT / "tasks"
 UPLOADS_DIR = PROJECT / "uploads"
 FIXTURES = PROJECT / "tests" / "fixtures"