实现L1航向伺服(路线A1): 吊舱角度直入控制律 + 桥接胶水 + 干跑入口

- visual_track_control: ControlSnapshot 加可选 los_beta_deg/los_alpha_deg,
  第④步角度直入优先否则回退像素路径(向后兼容); config 拆出 load_from_dict 供内嵌复用
- pod_bridge: BridgeConfig 内嵌 TrackingConfig + 新 HeadingServoConfig;
  bridge._build_snapshot 合成 β/α(姿态来自PX4/角度来自吊舱,信号双路适配无电机),
  step 按 heading_servo.enabled 切 L1/L2, DEGRADED_HOLD 补发刹车保 offboard 心跳;
  run() 循环频率按生效律取(修 L1 频率错配)
- run_bridge.py: 闭环 CLI 入口, --dry-run(S2 只接吊舱不发offboard) 与实飞优雅停机
- 配置落 L1 首飞值(slow_approach/0.2mps、垂直压低、无电机仅用脱靶量)
- 新增测试 29 条(vtc5+config9+bridgeL1 10+runner5); 全量 401 passed

utils/tests/pod_bridge/run_bridge_test.py

@@ -0,0 +1,82 @@
+"""run_bridge_test.py —— 桥接闭环入口单元测试（干跑桩 + 打印 + 干跑循环，无硬件）。
+
+重点守住 S2 干跑的安全属性：DryRunPx4 合成新鲜姿态让闭环能跑，但 send_* 只计数、
+**绝不下发 offboard**；串口未指定时报错退出而非静默。
+"""
+
+import asyncio
+from types import SimpleNamespace
+
+import pytest
+
+from pod_bridge.config import BridgeConfig
+from pod_bridge.protocol import Telemetry
+from pod_bridge.run_bridge import DryRunPx4, _format_status, _run_dry
+
+
+class FakePod:
+    def __init__(self, *frames):
+        self.inbox = list(frames)
+        self.sent = []
+        self.closed = False
+
+    def poll(self):
+        out, self.inbox = self.inbox, []
+        return out
+
+    def send(self, data):
+        self.sent.append(data)
+
+    def close(self):
+        self.closed = True
+
+
+# --- DryRunPx4：合成姿态 + 不发 offboard ------------------------------------
+def test_dry_run_px4_state_is_fresh():
+    px4 = DryRunPx4(now_ms_fn=lambda: 12345)
+    st = px4.own_state()
+    assert st.has_attitude and st.position_valid
+    assert st.time_ms == 12345 and st.position_time_ms == 12345
+
+
+def test_dry_run_px4_never_sends_offboard():
+    px4 = DryRunPx4()
+    assert asyncio.run(px4.start_offboard()) is True
+    assert asyncio.run(px4.send_velocity_heading(object())) is True
+    assert asyncio.run(px4.send_brake_hover()) is True
+    # 只计数，无任何硬件副作用
+    assert px4.velocity_calls == 1 and px4.brake_calls == 1
+
+
+def test_format_status_shows_mode_and_angles():
+    out = SimpleNamespace(mode=SimpleNamespace(name="VELOCITY_HEADING"),
+                          yaw_rate_dps=10.0, vx_body_mps=0.2, vz_mps=0.0)
+    tel = (Telemetry(status1=0b00000100, off_target_x_deg=10.0,
+                     off_target_y_deg=-3.0, frame_yaw_deg=0.0), 1000)
+    line = _format_status(1.0, out, tel, locked=True)
+    assert "VELOCITY_HEADING" in line
+    assert "+10.00" in line          # off_target_x
+    assert "locked=1" in line
+
+
+# --- 干跑循环 ---------------------------------------------------------------
+def test_run_dry_completes_and_downlinks_only(monkeypatch):
+    # 注入假串口：不碰真硬件，验证干跑循环能跑通并正常收尾
+    pod = FakePod(Telemetry(status1=0b00000100, off_target_x_deg=10.0))
+    monkeypatch.setattr("pod_bridge.run_bridge.PodSerial", lambda *a, **k: pod)
+    cfg = BridgeConfig()
+    cfg.heading_servo.enabled = True
+    cfg.tracking.control.frequency_hz = 200.0   # 加快节拍，缩短测试
+    args = SimpleNamespace(port="/dev/fake", duration=0.05, print_hz=0.0)
+
+    rc = asyncio.run(_run_dry(cfg, args))
+    assert rc == 0
+    assert pod.closed                          # 收尾关闭串口
+
+
+def test_run_dry_requires_port(monkeypatch):
+    monkeypatch.setattr("pod_bridge.run_bridge.PodSerial",
+                        lambda *a, **k: pytest.fail("无端口时不应打开串口"))
+    cfg = BridgeConfig()                        # pod_serial.port 默认空
+    args = SimpleNamespace(port=None, duration=0.0, print_hz=5.0)
+    assert asyncio.run(_run_dry(cfg, args)) == 2