feat(stream-bridge): 支持上游 sync 响应转 SSE 流式输出，记录 client/upstream 流模式差异

- 新增 sync_to_stream 桥接模块，将非 SSE 上游响应转换为 SSE 格式回传给流式客户端
- stream_pump 检测非 SSE 响应头后缓冲整包并通过桥接逻辑重写为 SSE 帧
- proxy handler 同步支持 sync→stream 聚合与转换（覆盖 openai/claude/gemini 四种格式）
- sync_products 补全 openai:cli 的完整流式事件聚合（text delta、reasoning、tool call 等）
- usage runtime 写入 client_requested_stream / upstream_is_stream 到 request_metadata
- SQL 查询层将两个布尔字段从 request_metadata jsonb 中提取并回传给前端
- 前端 status.ts 新增 resolveUsageStreamLabelSegments，优先读取 client_requested_stream
- RequestDetailDrawer 在流式转换场景下显示"客户端→上游"两段 Badge

apps/aether-gateway/src/tests/ai_execute/finalize_local_cli/compact.rs

@@ -395,7 +395,17 @@ async fn gateway_executes_openai_compact_openai_family_upstream_stream_via_local
             "object": "response",
             "model": "gpt-5",
             "status": "completed",
-            "output": [],
+            "output": [{
+                "type": "message",
+                "id": "resp_compact_openai_family_123_msg",
+                "role": "assistant",
+                "status": "completed",
+                "content": [{
+                    "type": "output_text",
+                    "text": "Hello Compact",
+                    "annotations": []
+                }]
+            }],
             "usage": {
                 "input_tokens": 2,
                 "output_tokens": 3,

apps/aether-gateway/src/tests/ai_execute/finalize_local_cli/direct.rs

@@ -387,7 +387,17 @@ async fn gateway_executes_openai_cli_sync_upstream_stream_via_local_finalize_res
             "object": "response",
             "model": "gpt-5-upstream",
             "status": "completed",
-            "output": [],
+            "output": [{
+                "type": "message",
+                "id": "resp_stream_001_msg",
+                "role": "assistant",
+                "status": "completed",
+                "content": [{
+                    "type": "output_text",
+                    "text": "Hello",
+                    "annotations": []
+                }]
+            }],
             "usage": {
                 "input_tokens": 1,
                 "output_tokens": 2,