feat(config): add subtitle CSS editor, nPlusOne.enabled flag, and fix se

- subtitleStyle.css / subtitleStyle.secondary.css replace flat style fields in the settings window
- ankiConnect.nPlusOne.enabled gates known-word cache independently of knownWords.highlightEnabled
- Settings search now covers all categories, narrows on multi-word terms, and hides editor-owned fields
- Default note-type picker to Kiku then Lapis; rename isLapis.sentenceCardModel default to "Lapis"

src/types/settings.ts

@@ -26,7 +26,8 @@ export type ConfigSettingsControl =
   | 'anki-note-type'
   | 'anki-field'
   | 'mpv-keybindings'
-  | 'color-list';
+  | 'color-list'
+  | 'css-declarations';
 
 export type ConfigSettingsRestartBehavior = 'hot-reload' | 'restart';
 
@@ -45,6 +46,7 @@ export interface ConfigSettingsField {
   advanced?: boolean;
   secret?: boolean;
   legacyHidden?: boolean;
+  settingsHidden?: boolean;
 }
 
 export type ConfigSettingsSnapshotValue = unknown;