refactor: remove dead code and enable noUnusedLocals (#292)

* refactor: remove dead code and enable noUnusedLocals

- delete launcher/jimaku.ts and the launcher Args/config jimaku* fields
  that only fed it (the SUBMINER_JIMAKU_* env vars had no effect)
- delete plugin/subminer/hover.lua; nothing has sent subminer-hover-token
  since Overlay 2.0
- drop never-read anilist.characterDictionary.refreshTtlHours and
  evictionPolicy (still hidden in the settings UI for old configs)
- drop unused root deps: eslint, @fontsource-variable/geist{,-mono}
  (stats/ declares its own)
- delete the committed draft renderer-performance plan doc
- turn on noUnusedLocals for typecheck and remove what it surfaced,
  including Windows focus-handoff values computed but never consumed

* docs(changes): add docs fragment and note retired hover messages

src/main/overlay-visibility-runtime.ts

@@ -15,9 +15,6 @@ export interface OverlayVisibilityRuntimeDeps {
   getSuspendVisibleOverlay?: () => boolean;
   getOverlayInteractionActive?: () => boolean;
   getWindowTracker: () => BaseWindowTracker | null;
-  getLastKnownWindowsForegroundProcessName?: () => string | null;
-  getWindowsOverlayProcessName?: () => string | null;
-  getWindowsFocusHandoffGraceActive?: () => boolean;
   getMacOSForegroundProbeActive?: () => boolean;
   getTrackerNotReadyWarningShown: () => boolean;
   setTrackerNotReadyWarningShown: (shown: boolean) => void;
@@ -61,9 +58,6 @@ export function createOverlayVisibilityRuntimeService(
         overlayInteractionActive: deps.getOverlayInteractionActive?.() ?? false,
         mainWindow,
         windowTracker,
-        lastKnownWindowsForegroundProcessName: deps.getLastKnownWindowsForegroundProcessName?.(),
-        windowsOverlayProcessName: deps.getWindowsOverlayProcessName?.() ?? null,
-        windowsFocusHandoffGraceActive: deps.getWindowsFocusHandoffGraceActive?.() ?? false,
         macOSForegroundProbeActive: deps.getMacOSForegroundProbeActive?.() ?? false,
         trackerNotReadyWarningShown: deps.getTrackerNotReadyWarningShown(),
         setTrackerNotReadyWarningShown: (shown: boolean) => {