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

package.json

@@ -114,8 +114,6 @@
   "author": "",
   "license": "GPL-3.0-or-later",
   "dependencies": {
-    "@fontsource-variable/geist": "^5.2.8",
-    "@fontsource-variable/geist-mono": "^5.2.7",
     "@xhayper/discord-rpc": "^1.3.4",
     "axios": "^1.20.0",
     "commander": "^14.0.3",
@@ -133,7 +131,6 @@
     "electron": "43.7.7",
     "electron-builder": "26.16.1",
     "esbuild": "^0.25.12",
-    "eslint": "^10.8.0",
     "prettier": "^3.8.1",
     "typescript": "^5.9.3",
     "undici": "7.29.1"