feat(cockpit_bridge): publish rov-failsafe-cause text for W1 status line

src/rov_mission/rov_mission/cockpit_bridge.py

@@ -64,6 +64,9 @@ class CockpitBridge(Node):
             # -1 initial value indicates no data received yet
             'rov-failsafe':  -1,
 
+            # Cause text for W1 status line, e.g. "Heartbeat Lost"
+            'rov-failsafe-cause': '',
+
             # Depth in metres below surface (positive = deeper)
             'rov-depth':     0.0,
 
@@ -225,6 +228,41 @@ class CockpitBridge(Node):
         with self._lock:
             self._values['rov-failsafe'] = int(msg.assessment_state)
 
+            # ------------------------------------------------------------
+            # rov-failsafe-cause — cause text for the W1 widget status line
+            # (e.g. "Heartbeat Lost", "Vehicle Disconnected").
+            #
+            # SHORTCUT: FailsafeStatus.msg has no dedicated cause field, so
+            # this parses it out of msg.message, which failsafe_monitor
+            # builds as either:
+            #   "<cause> | Assessment: <state> | State: <fsm> | Battery: <pct>%"
+            #   (a comms-loss cause prefix is present — see
+            #    failsafe_monitor._publish_status, DIR-7 cause-text
+            #    requirement)
+            # or, when nominal:
+            #   "Assessment: <state> | State: <fsm> | Battery: <pct>%"
+            #   (no distinct cause — the leading segment IS the Assessment
+            #   field, not a cause)
+            #
+            # Take the substring before the first "|", stripped of
+            # whitespace. If that leading segment itself starts with
+            # "Assessment:" there is no real cause prefix (nominal case) —
+            # publish an empty string instead of "Assessment: GREEN" etc.
+            #
+            # This is a string-parsing shortcut, not the proper fix. The
+            # correct implementation is a dedicated cause field on
+            # FailsafeStatus.msg (e.g. `string cause`), set directly by
+            # failsafe_monitor instead of being smuggled inside the
+            # human-readable message string — do this the next time
+            # FailsafeStatus.msg is revised. Reference: W1 cause-text
+            # display.
+            # ------------------------------------------------------------
+            leading_segment = msg.message.split('|', 1)[0].strip()
+            if leading_segment.startswith('Assessment:'):
+                self._values['rov-failsafe-cause'] = ''
+            else:
+                self._values['rov-failsafe-cause'] = leading_segment
+
     def _depth_cb(self, msg: Float64):
         """Update depth in metres from Float64 message."""
         with self._lock: