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

crates/aether-data/src/repository/usage/sql.rs

@@ -1683,7 +1683,25 @@ SELECT
   NULL::json AS client_response_headers,
   NULL::json AS client_response_body,
   NULL::bytea AS client_response_body_compressed,
-  NULL::json AS request_metadata,
+  CASE
+    WHEN ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')
+      OR ("usage".request_metadata->>'upstream_is_stream') IN ('true', 'false')
+      THEN jsonb_build_object(
+        'client_requested_stream',
+        CASE
+          WHEN ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')
+            THEN ("usage".request_metadata->>'client_requested_stream')::boolean
+          ELSE NULL
+        END,
+        'upstream_is_stream',
+        CASE
+          WHEN ("usage".request_metadata->>'upstream_is_stream') IN ('true', 'false')
+            THEN ("usage".request_metadata->>'upstream_is_stream')::boolean
+          ELSE NULL
+        END
+      )::json
+    ELSE NULL::json
+  END AS request_metadata,
   NULL::varchar AS http_request_body_ref,
   NULL::varchar AS http_provider_request_body_ref,
   NULL::varchar AS http_response_body_ref,
@@ -1903,7 +1921,25 @@ SELECT
   NULL::json AS client_response_headers,
   NULL::json AS client_response_body,
   NULL::bytea AS client_response_body_compressed,
-  NULL::json AS request_metadata,
+  CASE
+    WHEN ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')
+      OR ("usage".request_metadata->>'upstream_is_stream') IN ('true', 'false')
+      THEN jsonb_build_object(
+        'client_requested_stream',
+        CASE
+          WHEN ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')
+            THEN ("usage".request_metadata->>'client_requested_stream')::boolean
+          ELSE NULL
+        END,
+        'upstream_is_stream',
+        CASE
+          WHEN ("usage".request_metadata->>'upstream_is_stream') IN ('true', 'false')
+            THEN ("usage".request_metadata->>'upstream_is_stream')::boolean
+          ELSE NULL
+        END
+      )::json
+    ELSE NULL::json
+  END AS request_metadata,
   NULL::varchar AS http_request_body_ref,
   NULL::varchar AS http_provider_request_body_ref,
   NULL::varchar AS http_response_body_ref,