Improve global search

Add options to show only searches for
- pinned sources
- all sources
- sources with results

src/modules/metadata/Metadata.constants.ts

@@ -97,6 +97,7 @@ export const APP_METADATA_KEY_TO_TYPE = {
     mangaGridItemWidth: 'number',
     isPinned: 'boolean',
     lastUsedSourceId: 'string',
+    shouldShowOnlySourcesWithResults: 'boolean',
 } as const satisfies Record<AppMetadataKeys, 'auto' | 'string' | 'number' | 'boolean'>;
 
 export const VALID_APP_METADATA_KEYS = Object.keys(APP_METADATA_KEY_TO_TYPE);
@@ -149,6 +150,7 @@ export const GLOBAL_METADATA_KEYS: AppMetadataKeys[] = [
     'extensionLanguages',
     'showNsfw',
     'lastUsedSourceId',
+    'shouldShowOnlySourcesWithResults',
 
     // history
     'hideHistory',