新增: 飞书文件消息入站与补充注入链完善

- 文件消息入站:20MB 上限落盘引用,模型经 read_file 按需读盘;下载带 3 次退避+120s 超时防线,复用媒体域 hash 去重/OSS 双写
- 群聊门控对齐 u-claw 模式:前移至类型分流前,@自己/@所有人响应,未艾特静默旁观(原门控后置致未支持类型误回提示卡)
- 修复补充注入丢失:pending_injects 未消化计数+收敛出口续轮+桌面注入 IPC+前端本地气泡
- df-ai-core 测试构造器补 source 字段(溯源字段遗漏,全量门禁暴露)

crates/df-ai-core/src/provider.rs

@@ -310,6 +310,7 @@ mod tests {
             role: MessageRole::User,
             content: "字面量构造".into(),
             parts: None,
+            source: None,
             tool_call_id: None,
             tool_calls: None,
             model: None,
@@ -368,6 +369,7 @@ mod tests {
             role: MessageRole::Assistant,
             content: "answer".to_string(),
             parts: None,
+            source: None,
             tool_call_id: None,
             tool_calls: None,
             model: None,
@@ -429,6 +431,7 @@ mod tests {
             role: MessageRole::Assistant,
             content: "answer".to_string(),
             parts: None,
+            source: None,
             tool_call_id: None,
             tool_calls: None,
             model: None,