feat: 实现 executor 流式执行路径及完善 gateway 多格式 plan 构建

- Rust executor 新增流式 plan 支持，覆盖 openai/claude/gemini 的 chat/cli/video 格式
- Gateway 新增 finalize-sync、report-stream 端点及 stream report 模型
- 新增 video sync 操作(create/cancel/remix/delete)的 plan 构建
- 修正 OpenAI Responses(openai:cli) SSE 格式: 添加 event: 行、移除 [DONE] 哨兵
- 统一 OpenAI CLI normalizer 的 ID 生成方法

tests/api/handlers/base/test_cli_event_mixin.py

@@ -0,0 +1,38 @@
+from typing import Any
+
+from src.api.handlers.base.cli_event_mixin import CliEventMixin
+from src.api.handlers.base.stream_context import StreamContext
+
+
+class _DummyCliEventHandler(CliEventMixin):
+    request_id = "req-test"
+
+    def _process_event_data(
+        self,
+        ctx: StreamContext,
+        event_type: str,
+        data: dict[str, Any],
+    ) -> None:
+        del ctx, event_type, data
+
+
+def test_convert_sse_line_drops_done_for_openai_cli() -> None:
+    handler = _DummyCliEventHandler()
+    ctx = StreamContext(model="gpt-test", api_format="openai:cli")
+    ctx.client_api_format = "openai:cli"
+
+    lines, converted = handler._convert_sse_line(ctx, "data: [DONE]", [])
+
+    assert lines == []
+    assert converted == []
+
+
+def test_convert_sse_line_keeps_done_for_openai_chat() -> None:
+    handler = _DummyCliEventHandler()
+    ctx = StreamContext(model="gpt-test", api_format="openai:chat")
+    ctx.client_api_format = "openai:chat"
+
+    lines, converted = handler._convert_sse_line(ctx, "data: [DONE]", [])
+
+    assert lines == ["data: [DONE]"]
+    assert converted == []