perf(video): 新增 RKMPP DMA 采集编码通路并完善恢复逻辑

支持原生 HDMI 和 UVC 缓冲区导出，增加同步 RKMPP 编码及可选 MJPEG 硬件转码。
校验帧布局和缓冲区租约，在 DMA 不可用或编码失败时回退到复制通路。
保留自定义码率和 GOP 策略，重开采集时同步 HDMI 源帧率，并区分 UVC 超时状态。

验证：88 个视频测试通过（含 4 个新增回归测试）；ARM64 cargo check --tests 通过。

src/video/capture/status.rs

@@ -2,8 +2,32 @@
 
 use std::io;
 
+#[cfg(any(
+    test,
+    all(target_os = "linux", any(target_arch = "aarch64", target_arch = "arm"))
+))]
+use crate::video::device::VideoControlMode;
 use crate::video::signal::SignalStatus;
 
+#[cfg(any(
+    test,
+    all(target_os = "linux", any(target_arch = "aarch64", target_arch = "arm"))
+))]
+pub(crate) fn capture_recovery_status(
+    control_mode: VideoControlMode,
+    error: &io::Error,
+) -> SignalStatus {
+    if control_mode == VideoControlMode::Configurable && error.kind() == io::ErrorKind::TimedOut {
+        return SignalStatus::UvcCaptureStall;
+    }
+    match classify_capture_io_error(error) {
+        CaptureIoErrorKind::TransientSignal {
+            status: Some(status),
+        } => status,
+        _ => SignalStatus::NoSignal,
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum CaptureIoErrorKind {
     DeviceLost,
@@ -52,6 +76,33 @@ pub fn capture_error_log_key(err: &io::Error) -> String {
 mod tests {
     use super::*;
 
+    #[test]
+    fn recovery_distinguishes_uvc_stalls_from_hdmi_signal_loss() {
+        let timeout = io::Error::from(io::ErrorKind::TimedOut);
+        assert_eq!(
+            capture_recovery_status(VideoControlMode::Configurable, &timeout),
+            SignalStatus::UvcCaptureStall
+        );
+        assert_eq!(
+            capture_recovery_status(VideoControlMode::SourceFollowing, &timeout),
+            SignalStatus::NoSignal
+        );
+        assert_eq!(
+            capture_recovery_status(
+                VideoControlMode::Configurable,
+                &io::Error::from_raw_os_error(71)
+            ),
+            SignalStatus::UvcUsbError
+        );
+        assert_eq!(
+            capture_recovery_status(
+                VideoControlMode::SourceFollowing,
+                &io::Error::from_raw_os_error(5)
+            ),
+            SignalStatus::NoSignal
+        );
+    }
+
     #[test]
     fn maps_known_signal_status_strings() {
         assert_eq!(