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/test_web_e2e.py

@@ -1,11 +1,15 @@
 """
 Playwright E2E tests for COBOL-Java Migration Platform Web UI.
-Server must be running: python -m uvicorn web.api:app --host 127.0.0.1 --port 8000
+Server must be running: python -m uvicorn web.api:app --host 127.0.0.1 --port $TEST_PORT
+(端口经 TEST_PORT 环境变量配置, 默认 8000)
 """
+import os
+
 import pytest
 from playwright.sync_api import Page, expect, sync_playwright
 
-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}"
 
 
 @pytest.fixture(scope="module")
@@ -53,13 +57,14 @@ def test_form_elements_present(page: Page):
 def test_submit_empty_form(page: Page):
     """验证空表单提交返回 422 (缺少必填字段)"""
     page.goto(BASE_URL)
-    result = page.evaluate("""
+    js = """
         (async () => {
             const fd = new FormData();
-            const r = await fetch('http://127.0.0.1:8000/verify', { method: 'POST', body: fd });
+            const r = await fetch('__BASE_URL__/verify', { method: 'POST', body: fd });
             return r.status;
         })()
-    """)
+    """.replace("__BASE_URL__", BASE_URL)
+    result = page.evaluate(js)
     assert result == 422
 
 
@@ -73,7 +78,7 @@ def test_submit_with_files(page: Page):
     page.set_input_files("input[name=mapping]",
         "tests/fixtures/simple.yaml")
     # 用 evaluate 直接调 API 绕过 webkitdirectory 限制
-    result = page.evaluate("""
+    js = """
         (async () => {
             const fd = new FormData();
             fd.append('copybook', new Blob(['test'], {type:'text/plain'}), 'test.cpy');
@@ -81,10 +86,11 @@ def test_submit_with_files(page: Page):
             fd.append('java_src', new Blob(['test'], {type:'text/plain'}), 'test.java');
             fd.append('mapping', new Blob(['test'], {type:'text/plain'}), 'test.yaml');
             fd.append('runner', 'native');
-            const r = await fetch('http://127.0.0.1:8000/verify', { method: 'POST', body: fd });
+            const r = await fetch('__BASE_URL__/verify', { method: 'POST', body: fd });
             return { status: r.status, body: await r.json() };
         })()
-    """)
+    """.replace("__BASE_URL__", BASE_URL)
+    result = page.evaluate(js)
     assert result["status"] == 202
     assert "task_id" in result["body"]