feat(codex): 拆分openai:compact为独立端点，简化Codex请求为透传模式

- 新增openai:compact端点类型(EndpointKind.COMPACT)，独立于openai:cli
- OpenAICompactAdapter继承OpenAICliAdapter，自动标记compact模式
- Codex请求补丁改为纯透传：仅清理内部标记，不再修改客户端payload
- stream_policy支持openai:compact独立策略，compact端点移除stream字段
- candidate_builder支持compact回退到cli端点
- auth_type: vertex_ai重命名为service_account，保持向后兼容
- Vertex Provider新增api_formats与auth_type组合校验
- KeyAllowedModels对话框改为从Provider获取模型，展示provider_model_name
- Dialog内Select组件自动禁用Portal，修复层级遮挡问题
- 新增Codex compact端点回填迁移脚本

tests/services/test_upstream_stream_policy.py

@@ -59,6 +59,15 @@ def test_get_upstream_stream_policy_codex_compact_forces_non_stream() -> None:
         set_codex_request_context(None)
 
 
+def test_get_upstream_stream_policy_codex_openai_compact_defaults_to_auto() -> None:
+    ep = _DummyEndpoint(
+        api_format="openai:compact",
+        config=None,
+        provider=SimpleNamespace(provider_type="codex"),
+    )
+    assert get_upstream_stream_policy(ep) == UpstreamStreamPolicy.AUTO
+
+
 def test_enforce_stream_mode_for_upstream_openai_chat_sets_stream_options_usage() -> None:
     body = {"stream": False}
     out = enforce_stream_mode_for_upstream(
@@ -79,3 +88,30 @@ def test_enforce_stream_mode_for_upstream_gemini_drops_stream_field() -> None:
     )
     assert "stream" not in out
     assert out["foo"] == "bar"
+
+
+def test_enforce_stream_mode_for_upstream_openai_compact_drops_stream_field() -> None:
+    body = {"stream": True, "foo": "bar"}
+    out = enforce_stream_mode_for_upstream(
+        body,
+        provider_api_format="openai:compact",
+        upstream_is_stream=True,
+    )
+    assert "stream" not in out
+    assert out["foo"] == "bar"
+
+
+def test_enforce_stream_mode_for_upstream_codex_compact_keeps_stream_absent() -> None:
+    body = {"stream": True, "foo": "bar"}
+    try:
+        set_codex_request_context(CodexRequestContext(is_compact=True))
+        out = enforce_stream_mode_for_upstream(
+            body,
+            provider_api_format="openai:cli",
+            upstream_is_stream=False,
+        )
+    finally:
+        set_codex_request_context(None)
+
+    assert "stream" not in out
+    assert out["foo"] == "bar"