refactor(ipc): remove dead preload methods and the ASS line broadcast (#293)

Drop 16 overlay preload methods with no caller (onSubtitleAss,
getCurrentSubtitleAss, onVisibility, getOverlayVisibility,
openYomitanSettings, quitApp, toggleOverlay, getMecabStatus,
setMecabEnabled, getKeybindings, saveControllerPreference,
getAnkiConnectStatus, setAnkiConnectEnabled, clearAnkiConnectHistory,
cycleRuntimeOption, appendClipboardVideoToQueue) along with their
IPC_CHANNELS keys, handlers, validators and dep plumbing.

With both ASS consumers gone, stop observing sub-text/ass in mpv and
remove the subtitle-ass-change event chain and appState.currentSubAssText.
The main-process functions these wrapped stay; tray, CLI, shortcuts and
session actions still use them.

src/main/runtime/mpv-main-event-main-deps.ts

@@ -46,7 +46,6 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
     activeParsedSubtitleSource?: string | null;
     currentMediaPath?: string | null;
     currentSubText: string;
-    currentSubAssText: string;
     currentSubtitleData?: SubtitleData | null;
     playbackPaused: boolean | null;
     previousSecondarySubVisibility: boolean | null;
@@ -300,11 +299,6 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
       ? (trackList: unknown[] | null) => deps.onSubtitleTrackListChange!(trackList)
       : undefined,
     refreshDiscordPresence: () => deps.refreshDiscordPresence(),
-    setCurrentSubAssText: (text: string) => {
-      deps.appState.currentSubAssText = text;
-    },
-    broadcastSubtitleAss: (text: string) =>
-      deps.broadcastToOverlayWindows('subtitle-ass:set', text),
     broadcastSecondarySubtitle: (text: string) => {
       if (deps.onSecondarySubtitleChange) {
         deps.onSecondarySubtitleChange(text);