bridge: show the signal path as a rig row

health_item() turns the health.json gig-log publishes into one more panel item,
through the same tray_summary() the tray renders, so the two faces cannot
disagree. A stale observer is 'broken', no observer is 'absent'; neither can
read as up.

tools/bridge/rig.py

@@ -56,6 +56,7 @@ THERMAL_CONF = Path("/etc/thermal-mode.conf")
 sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
 
 from rig_units import SERVICES as _INVENTORY  # noqa: E402
+import rig_health  # noqa: E402  (the one health.json gig-log publishes; read-only here)
 
 # The panel does not care about boot policy (that is `--ensure`'s business), so
 # it keeps its own 4-tuple shape rather than spreading a 5th field everywhere.
@@ -174,6 +175,23 @@ def _leds_state(state, detail):
     return "down", f"{detail} — board is plugged in but DARK, start this"
 
 
+_HEALTH_STATE = {"ok": "up", "degraded": "down", "down": "broken", "stale": "broken"}
+
+
+def health_item(h: dict) -> dict:
+    """The signal path as one more panel row, from the same document and the same
+    wording the tray uses (rig_health.tray_summary), so the two faces cannot
+    disagree. `unknown` means gig-log is not running: that is `absent` here, which
+    the panel draws as not-applicable, never as a green row."""
+    s = rig_health.tray_summary(h)
+    detail = s["row"].removeprefix("rig: ")
+    if s["tip"]:
+        detail += " — " + s["tip"][0].removeprefix("rig: ")
+    return {"key": "rig-health", "name": "signal path", "kind": "health",
+            "blurb": "clock, surface driver, sound engine (gig-log)",
+            "state": _HEALTH_STATE.get(h.get("overall"), "absent"), "detail": detail}
+
+
 def status():
     """Every piece of the rig, with the state the reader actually needs."""
     lines = L._cmdlines()                    # one /proc scan for the whole snapshot
@@ -224,6 +242,8 @@ def status():
                   "state": "up" if _lcxl() else "down",
                   "detail": "connected" if _lcxl() else "not detected"})
 
+    items.append(health_item(rig_health.read_health()))
+
     return {"items": items, "gear": gear(), "converge": _job.state()}
 
 

tools/bridge/tests/test_rig.py

@@ -146,3 +146,26 @@ def test_converge_never_makes_sound(monkeypatch):
     R._Converge()._run(launch_apps=False)
     assert "--audio" not in seen["argv"]
     assert "--converge" in seen["argv"]
+
+
+# ── the signal path row (rig_health) ───────────────────────────────
+def _h(overall, **checks):
+    return {"overall": overall, "checks": {n: {"state": s, "detail": d} for n, (s, d) in checks.items()}}
+
+
+def test_health_row_is_up_only_when_the_observer_says_ok():
+    assert R.health_item(_h("ok"))["state"] == "up"
+
+
+def test_health_row_is_broken_when_down_and_names_the_failing_check():
+    it = R.health_item(_h("down", audio_clock=("fail", "no hardware clock")))
+    assert it["state"] == "broken" and "audio_clock" in it["detail"]
+
+
+def test_a_stale_observer_is_broken_not_up():
+    """A dead observer must never read green."""
+    assert R.health_item({"overall": "stale", "detail": "old", "checks": {}})["state"] == "broken"
+
+
+def test_no_observer_is_absent_not_up():
+    assert R.health_item({"overall": "unknown", "checks": {}})["state"] == "absent"