feat(FN-3576): restore plugin setting group field and grouped agent browser

This merge restores plugin setting group functionality in the dashboard (FN-3576), adds documentation for plugin authoring, and improves test isolation by broadening runtime ignore lists for live fusion app paths in the isolation checker script. The feature touches the PluginManager component with n

Fusion-Task-Id: FN-3576

docs/PLUGIN_AUTHORING.md

@@ -149,6 +149,13 @@ const settingsSchema: Record<string, PluginSettingSchema> = {
 
 ### Setting Types
 
+Common optional fields on all setting types:
+
+- `group?: string` — Optional heading used by the dashboard to render settings in grouped sections (for example: `"General"`, `"Browser"`, `"Prompt Contributions"`, `"Skills"`).
+- `description?: string` — Helper text shown below the setting label.
+- `required?: boolean` — Marks the field as required.
+- `defaultValue?: unknown` — Default value used when no user value is provided.
+
 | Type | Description | Extra Fields |
 |------|-------------|--------------|
 | `"string"` | Text input | `multiline?: boolean` (renders textarea) |
@@ -196,6 +203,7 @@ const settingsSchema: Record<string, PluginSettingSchema> = {
   enabled: {
     type: "boolean",
     label: "Enable Feature",
+    group: "General",
     defaultValue: true,
   },
   
@@ -212,6 +220,7 @@ const settingsSchema: Record<string, PluginSettingSchema> = {
     type: "array",
     label: "Tags",
     description: "Tags to track",
+    group: "Skills",
     itemType: "string",
     defaultValue: ["bug", "feature"],
   },