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

launcher/smoke.e2e.test.ts

@@ -543,7 +543,6 @@ test(
         const appStartEntries = readJsonLines(appStartPath);
         const appStopEntries = readJsonLines(appStopPath);
         const controlEntries = readJsonLines(controlServer.logPath);
-        const mpvEntries = readJsonLines(path.join(smokeCase.artifactsDir, 'fake-mpv.log'));
 
         assert.equal(result.status, 0);
         if (process.platform === 'linux') {