feat: surgery pipeline API, video inference, voice confirm, and tests

- Add FastAPI routes for surgery start/end, results, pending confirmation (WAV upload), and health checks.
- Implement RTSP/Hikvision capture, consumable classification, session manager, MinIO/Baidu voice resolution, and DB persistence.
- Add documentation (client API, video backends, staging checklist) and sample camera/RTSP config.
- Add pytest suite (API contract, session manager, voice, repositories, pipeline persistence) and httpx dev dependency.
- Replace deprecated HTTP_422_UNPROCESSABLE_ENTITY with HTTP_422_UNPROCESSABLE_CONTENT.
- Fix SurgeryPipeline DB reads to use an explicit transaction with autobegin disabled.

Made-with: Cursor

app/services/video/rtsp_capture.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+import time
+from dataclasses import dataclass
+from typing import Any
+
+import cv2
+import numpy as np
+from loguru import logger
+
+
+@dataclass
+class RtspCapture:
+    """Thin OpenCV RTSP wrapper (blocking). Use from asyncio via to_thread."""
+
+    url: str
+    open_timeout_sec: float
+
+    def __post_init__(self) -> None:
+        self._cap: cv2.VideoCapture | None = None
+
+    def open(self) -> None:
+        self._cap = cv2.VideoCapture(self.url, cv2.CAP_FFMPEG)
+        if not self._cap.isOpened():
+            raise RuntimeError(f"RTSP open failed (isOpened=False): {self.url!r}")
+        # Reduce internal buffering where supported
+        try:
+            self._cap.set(cv2.CAP_PROP_BUFFERSIZE, 1)
+        except Exception:
+            pass
+        deadline = time.monotonic() + self.open_timeout_sec
+        while time.monotonic() < deadline:
+            ok, frame = self._cap.read()
+            if ok and frame is not None:
+                return
+            time.sleep(0.05)
+        raise TimeoutError(
+            f"RTSP first frame timeout after {self.open_timeout_sec}s: {self.url!r}"
+        )
+
+    def read(self) -> tuple[bool, np.ndarray | None]:
+        if self._cap is None:
+            return False, None
+        return self._cap.read()
+
+    def release(self) -> None:
+        if self._cap is not None:
+            try:
+                self._cap.release()
+            except Exception as exc:
+                logger.debug("VideoCapture.release: {}", exc)
+            self._cap = None
+
+    @property
+    def cap(self) -> Any:
+        return self._cap