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/config/template.ts

@@ -18,10 +18,6 @@ const TOP_LEVEL_SECTION_DESCRIPTION_BY_KEY = new Map(
   CONFIG_TEMPLATE_SECTIONS.map((section) => [String(section.key), section.description[0] ?? '']),
 );
 const SUBTITLE_CSS_SCOPES: SubtitleCssScope[] = ['primary', 'secondary', 'sidebar'];
-const HIDDEN_TEMPLATE_PATHS = [
-  'anilist.characterDictionary.evictionPolicy',
-  'anilist.characterDictionary.refreshTtlHours',
-];
 
 function normalizeCommentText(value: string): string {
   return value.replace(/\s+/g, ' ').replace(/\*\//g, '*\\/').trim();
@@ -176,9 +172,6 @@ function renderSection(
 function createTemplateConfig(config: ResolvedConfig): ResolvedConfig {
   const templateConfig = deepCloneConfig(config);
   foldSubtitleCssManagedDefaults(templateConfig);
-  for (const hiddenPath of HIDDEN_TEMPLATE_PATHS) {
-    deleteValueAtPath(templateConfig, hiddenPath);
-  }
   if (templateConfig.keybindings.length === 0) {
     templateConfig.keybindings = DEFAULT_KEYBINDINGS.map((binding) => ({
       key: binding.key,