fix: make launch file sole source of truth for plugin enablement

- Default plugins to empty in YAML params (prevents loading with
  empty paths if launch resolution fails)
- Always override plugins list from launch file (even when empty)

Addresses PR review feedback.

Author: bburda

demos/moveit_pick_place/config/medkit_params.yaml

@@ -26,10 +26,8 @@ diagnostics:
         runtime:
           create_synthetic_components: false  # Manifest defines components
 
-      # Plugin configuration (paths set by launch file)
-      plugins: ["graph_provider", "procfs_introspection"]
-      plugins.graph_provider.path: ""
-      plugins.procfs_introspection.path: ""
+      # Plugin configuration (set by launch file when .so paths are resolved)
+      plugins: [""]
 
 # Fault Manager configuration (runs in root namespace)
 fault_manager:

demos/moveit_pick_place/launch/demo.launch.py

@@ -64,8 +64,7 @@ def generate_launch_description():
     if procfs_plugin_path:
         active_plugins.append('procfs_introspection')
         plugin_overrides['plugins.procfs_introspection.path'] = procfs_plugin_path
-    if active_plugins:
-        plugin_overrides['plugins'] = active_plugins
+    plugin_overrides['plugins'] = active_plugins
 
     # Launch configuration variables
     use_sim_time = LaunchConfiguration("use_sim_time", default="False")

demos/moveit_pick_place/launch/demo_gazebo.launch.py

@@ -83,8 +83,7 @@ def generate_launch_description():
     if procfs_plugin_path:
         active_plugins.append('procfs_introspection')
         plugin_overrides['plugins.procfs_introspection.path'] = procfs_plugin_path
-    if active_plugins:
-        plugin_overrides['plugins'] = active_plugins
+    plugin_overrides['plugins'] = active_plugins
 
     # Factory world file path
     factory_world = os.path.join(

demos/sensor_diagnostics/config/medkit_params.yaml

@@ -24,10 +24,8 @@ diagnostics:
         runtime:
           create_synthetic_components: false  # Manifest defines components
 
-      # Plugin configuration (paths set by launch file)
-      plugins: ["graph_provider", "procfs_introspection"]
-      plugins.graph_provider.path: ""
-      plugins.procfs_introspection.path: ""
+      # Plugin configuration (set by launch file when .so paths are resolved)
+      plugins: [""]
 
 # Fault Manager configuration (runs in root namespace)
 fault_manager:

demos/sensor_diagnostics/launch/demo.launch.py

@@ -65,8 +65,7 @@ def generate_launch_description():
     if procfs_plugin_path:
         active_plugins.append('procfs_introspection')
         plugin_overrides['plugins.procfs_introspection.path'] = procfs_plugin_path
-    if active_plugins:
-        plugin_overrides['plugins'] = active_plugins
+    plugin_overrides['plugins'] = active_plugins
 
     # Launch arguments
     use_sim_time = LaunchConfiguration("use_sim_time", default="false")

demos/turtlebot3_integration/config/medkit_params.yaml

@@ -25,10 +25,8 @@ diagnostics:
         runtime:
           create_synthetic_components: false  # Manifest defines components
 
-      # Plugin configuration (paths set by launch file)
-      plugins: ["graph_provider", "procfs_introspection"]
-      plugins.graph_provider.path: ""
-      plugins.procfs_introspection.path: ""
+      # Plugin configuration (set by launch file when .so paths are resolved)
+      plugins: [""]
 
 # Fault Manager configuration (runs in root namespace)
 fault_manager:

demos/turtlebot3_integration/launch/demo.launch.py

@@ -66,8 +66,7 @@ def generate_launch_description():
     if procfs_plugin_path:
         active_plugins.append('procfs_introspection')
         plugin_overrides['plugins.procfs_introspection.path'] = procfs_plugin_path
-    if active_plugins:
-        plugin_overrides['plugins'] = active_plugins
+    plugin_overrides['plugins'] = active_plugins
 
     # Gazebo world file
     world_file = os.path.join(turtlebot3_gazebo_dir, "worlds", "turtlebot3_world.world")