fix(bringup): wire mode_profile_loader into rov_full.launch.py

mode_profile_loader was built and committed 7 Jul 2026 (4e48dc2) but never
added to any launch file, so /rov/mode/profile has had zero publishers at
runtime on every startup since — confirmed 12 Jul 2026 on RPi5 via
`ros2 node list` (no mode node) and `ros2 topic info /rov/mode/profile`
(Publisher count: 0, 2 subscribers waiting). The entire operating-mode
profile system has been dark since it was built; failsafe_monitor's
health_role has been silently running on its gate default the whole time
rather than the actual configured mode.

Adds the Node action (package rov_mission, executable mode_profile_loader)
alongside the other core nodes, before Perception, so failsafe_monitor and
cockpit_bridge — both latched subscribers to its output — wait as little as
possible on a publisher. respawn=True/respawn_delay=5.0 to match the other
core nodes (c099c00, a5e1c99); not on the respawn exclusion list.

mode_profile_loader.py and mode_profiles.yaml are untouched — this closes
the wiring gap only.

src/rov_bringup/launch/rov_full.launch.py

@@ -67,6 +67,45 @@ def generate_launch_description():
             ),
         ),
 
+        # ------------------------------------------------------------------
+        # Mode profile loader — loads mode_profiles.yaml and publishes the
+        # resolved operating-mode profile (ROV / AUV / saved hybrid) on
+        # /rov/mode/profile, latched (TRANSIENT_LOCAL). It is the single
+        # source of truth for health_role (gate/advisory) and every other
+        # mode-derived flag; failsafe_monitor (mode-dependent recovery,
+        # 2a3e577) and cockpit_bridge (external/rov-* data lake variables)
+        # both subscribe to it and have nothing correct to fall back on
+        # until it publishes — failsafe_monitor's health_role in particular
+        # defaults to the conservative "gate" assumption until the first
+        # message arrives, so the sooner this node is up, the sooner that
+        # default stops being a guess. Placed here (with the other core
+        # nodes, before Perception) rather than down in the Mission stack
+        # further below, specifically so it does not sit behind Perception
+        # startup on the way to publishing.
+        #
+        # GAP: this node was built and committed on 7 Jul 2026 (4e48dc2) but
+        # was never added to this launch file, so /rov/mode/profile had zero
+        # publishers at runtime on every startup since — confirmed 12 Jul
+        # 2026 via `ros2 node list` (no mode node present) and
+        # `ros2 topic info /rov/mode/profile` (Publisher count: 0, 2
+        # subscribers waiting). This entry closes that gap.
+        #
+        # respawn=True/respawn_delay=5.0 for the same reason as the other
+        # core nodes (c099c00, a5e1c99): if this node dies, the entire mode
+        # system goes dark and health_role silently falls back to its gate
+        # default — exactly the silent-degradation case respawn policy
+        # exists to catch. Not on the respawn exclusion list (mavros_node,
+        # recording_manager, perception, foxglove_bridge).
+        # ------------------------------------------------------------------
+        Node(
+            package='rov_mission',
+            executable='mode_profile_loader',
+            name='mode_profile_loader',
+            output='screen',
+            respawn=True,
+            respawn_delay=5.0,
+        ),
+
         # Perception stack
         IncludeLaunchDescription(
             PythonLaunchDescriptionSource(