修复: 测试进程 comctl32 延迟加载与流式 usage 断言同步

lib 测试无内嵌窗口清单,GUI 依赖静态绑定 comctl32 缺导出致测试进程启动即崩
改 DELAYLOAD 推迟绑定,测试进程不触碰 GUI 入口;app 端清单选 v6 行为不变
流式 usage 改为 message_start 同帧携带初始快照,断言对齐该语义

crates/df-ai/src/openai_compat.rs

@@ -696,10 +696,14 @@ mod tests {
         assert_eq!(c.delta, "");
         assert!(acc.is_none(), "此 chunk 无 usage 字段，累加器仍为 None");
 
-        // 4) usage-only chunk（choices=[]）携带累计 usage → 覆盖累加器
+        // 4) usage-only chunk（choices=[]）携带累计 usage → 覆盖累加器，并同帧带出快照
+        // （6bafdcd 起 usage 与累加器同帧挂载，中途断连也能拿到真实 usage，非仅 [DONE] 带出）
         let c = apply_openai_sse(&usage_only_chunk(12, 34), &mut acc);
         assert!(!c.finished);
-        assert!(c.usage.is_none(), "非 [DONE] chunk 不带出 usage");
+        let u = c.usage.expect("usage-only chunk 应同帧带出累积 usage 快照");
+        assert_eq!(u.prompt_tokens, 12);
+        assert_eq!(u.completion_tokens, 34);
+        assert_eq!(u.total_tokens, 46);
         let acc = acc.expect("累加器应已被 usage-only chunk 覆盖写入");
         assert_eq!(acc.prompt_tokens, 12);
         assert_eq!(acc.completion_tokens, 34);
@@ -712,7 +716,11 @@ mod tests {
         let mut acc: Option<TokenUsage> = None;
         let c = apply_openai_sse(&text_chunk_with_usage("", "stop", 100, 200), &mut acc);
         assert!(c.finished);
-        assert!(c.usage.is_none(), "非 [DONE] 不带出 usage，仅覆盖累加器");
+        // 6bafdcd 起 usage 与累加器同帧挂载：finish 帧即带快照，下游不必等 [DONE]
+        let u = c.usage.expect("finish 帧应同帧带出累积 usage 快照");
+        assert_eq!(u.prompt_tokens, 100);
+        assert_eq!(u.completion_tokens, 200);
+        assert_eq!(u.total_tokens, 300);
         let acc = acc.expect("末段 chunk 的 usage 应已覆盖累加器");
         assert_eq!(acc.prompt_tokens, 100);
         assert_eq!(acc.completion_tokens, 200);