Add support for runtime error status in plugins

Distinguish a loaded plugin whose
capability errored (RuntimeError,
warn-styled, stays checked) from a
load-time Error. Status now derives
via resolve_plugin_status(); enum
ordinal keeps dialog sort priority.
Unloading clears stale errors.

src/slic3r/GUI/PluginStatus.hpp

@@ -11,6 +11,7 @@ namespace Slic3r
             // IMPORTANT: ordinal order is the Plugins dialog Status sort priority.
             Activated,
             Error,
+            RuntimeError,
             Inactive,
             Loading
         };
@@ -21,11 +22,28 @@ namespace Slic3r
             {
             case PluginStatus::Activated: return "Activated";
             case PluginStatus::Error: return "Error";
+            case PluginStatus::RuntimeError: return "RuntimeError";
             case PluginStatus::Inactive: return "Inactive";
             case PluginStatus::Loading: return "Loading";
             }
 
             return "Inactive";
         }
+
+        // why: a plugin whose module is live but whose catalog carries an error is a
+        //   RUNTIME fault (e.g. a capability rejected at register time) - it stays
+        //   loaded/checked and is only flagged, distinct from a load-time Error where
+        //   the module never came up. Loading wins over both so an in-flight reload
+        //   never flashes an error.
+        inline PluginStatus resolve_plugin_status(bool loading, bool has_error, bool is_loaded)
+        {
+            if (loading)
+                return PluginStatus::Loading;
+            if (has_error)
+                return is_loaded ? PluginStatus::RuntimeError : PluginStatus::Error;
+            if (is_loaded)
+                return PluginStatus::Activated;
+            return PluginStatus::Inactive;
+        }
     }
 } // namespace Slic3r::GUI