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/runtime/overlay-visibility-runtime-main-deps.ts

@@ -14,10 +14,6 @@ export function createBuildOverlayVisibilityRuntimeMainDepsHandler(
     getSuspendVisibleOverlay: () => deps.getSuspendVisibleOverlay?.() ?? false,
     getOverlayInteractionActive: () => deps.getOverlayInteractionActive?.() ?? false,
     getWindowTracker: () => deps.getWindowTracker(),
-    getLastKnownWindowsForegroundProcessName: () =>
-      deps.getLastKnownWindowsForegroundProcessName?.() ?? null,
-    getWindowsOverlayProcessName: () => deps.getWindowsOverlayProcessName?.() ?? null,
-    getWindowsFocusHandoffGraceActive: () => deps.getWindowsFocusHandoffGraceActive?.() ?? false,
     getMacOSForegroundProbeActive: () => deps.getMacOSForegroundProbeActive?.() ?? false,
     getTrackerNotReadyWarningShown: () => deps.getTrackerNotReadyWarningShown(),
     setTrackerNotReadyWarningShown: (shown: boolean) => deps.setTrackerNotReadyWarningShown(shown),