feat: frontend perf and a11y pass, plus mod visuals, hero main menu, Simple Voice Chat and vanilla chat autocomplete

Frontend:
- replace the i18next stack with a small typed i18n module
- hero clouds removed, llms.txt, HUD widget ARIA fixes and tests

Mod:
- TargetESP constellation mode; tracker and colors extracted
- JumpCircles: 7 new shapes, shared animation and color pipeline
- KillEffect blood mode with Burst/Fountain/Ring/Spray styles
- main menu: menuLayout setting (orbs/hero) and hero screen
- Simple Voice Chat soft integration: VoiceChat module and HUD panel
- renderer/quick: static Draw facade with glass outline
- vanilla chat: Baritone-style autocomplete popup for the % command prefix

frontend/src/shared/i18n/core.ts

@@ -0,0 +1,124 @@
+/**
+ * Tiny i18n core (replaces i18next): namespaced dictionaries, `{{var}}` interpolation,
+ * CLDR plural suffixes (`key_one` / `key_few` / `key_other`), fallback to English.
+ * Typed keys are derived from the Russian dictionaries (English must match them).
+ */
+
+import type { accountRu } from '@features/account/i18n/ru'
+import type { authRu } from '@features/auth/i18n/ru'
+import type { clickguiRu } from '@features/clickgui/i18n/ru'
+import type { configsRu } from '@features/configs/i18n/ru'
+import type { deviceLinkRu } from '@features/device-link/i18n/ru'
+import type { downloadRu } from '@features/download/i18n/ru'
+import type { landingRu } from '@features/landing/i18n/ru'
+import type { profileRu } from '@features/profile/i18n/ru'
+import type { showcaseRu } from '@features/showcase/i18n/ru'
+import type { themesRu } from '@features/themes/i18n/ru'
+import type { commonRu } from '@shared/i18n/common.ru'
+
+export type Lang = 'ru' | 'en'
+
+export interface Resources {
+  common: typeof commonRu
+  auth: typeof authRu
+  landing: typeof landingRu
+  themes: typeof themesRu
+  clickgui: typeof clickguiRu
+  download: typeof downloadRu
+  deviceLink: typeof deviceLinkRu
+  account: typeof accountRu
+  configs: typeof configsRu
+  showcase: typeof showcaseRu
+  profile: typeof profileRu
+}
+
+export type Namespace = keyof Resources & string
+
+type PluralSuffix = 'zero' | 'one' | 'two' | 'few' | 'many' | 'other'
+type Paths<T> = T extends string
+  ? never
+  : { [K in keyof T & string]: T[K] extends string ? (K extends `${infer B}_${PluralSuffix}` ? B : K) : `${K}.${Paths<T[K]>}` }[keyof T & string]
+
+export type KeyOf<N extends Namespace> = Paths<Resources[N]>
+type Qualified = { [N in Namespace]: `${N}:${KeyOf<N>}` }[Namespace]
+
+export type TOptions = { count?: number } & Record<string, string | number | undefined>
+export type TFunction<N extends Namespace = 'common'> = (key: KeyOf<N> | Qualified, options?: TOptions) => string
+
+type Dict = { [k: string]: string | Dict }
+type Bundles = Record<Lang, Record<string, Dict>>
+
+const STORAGE_KEY = 'lv_lang'
+const listeners = new Set<() => void>()
+
+function lookup(dict: Dict | undefined, path: string): string | undefined {
+  let node: string | Dict | undefined = dict
+  for (const part of path.split('.')) {
+    if (node === undefined || typeof node === 'string') return undefined
+    node = node[part]
+  }
+  return typeof node === 'string' ? node : undefined
+}
+
+/** Only an actual `ru` locale gets Russian; every other language falls back to English. */
+export function detectLanguage(): Lang {
+  try {
+    const saved = localStorage.getItem(STORAGE_KEY)
+    if (saved === 'ru' || saved === 'en') return saved
+  } catch {
+    // Storage blocked: fall through to the browser language.
+  }
+  return typeof navigator !== 'undefined' && navigator.language?.toLowerCase().startsWith('ru') ? 'ru' : 'en'
+}
+
+export class I18n {
+  language: Lang
+  private readonly bundles: Bundles
+
+  constructor(bundles: Bundles, lng?: Lang) {
+    this.bundles = bundles
+    this.language = lng ?? detectLanguage()
+    document.documentElement.lang = this.language
+  }
+
+  private resolve(lng: Lang, ns: string, key: string, count?: number): string | undefined {
+    const dict = this.bundles[lng][ns]
+    if (count !== undefined) {
+      const plural = lookup(dict, `${key}_${new Intl.PluralRules(lng).select(count)}`) ?? lookup(dict, `${key}_other`)
+      if (plural !== undefined) return plural
+    }
+    return lookup(dict, key)
+  }
+
+  getFixedT<N extends Namespace = 'common'>(lng: Lang, ns: N | readonly N[]): TFunction<N> {
+    const first = (Array.isArray(ns) ? ns[0] : ns) as string
+    return ((rawKey: string, options: TOptions = {}) => {
+      const colon = rawKey.indexOf(':')
+      const [space, key] = colon === -1 ? [first, rawKey] : [rawKey.slice(0, colon), rawKey.slice(colon + 1)]
+      const text = this.resolve(lng, space, key, options.count) ?? this.resolve('en', space, key, options.count)
+      if (text === undefined) return key
+      return text.replace(/\{\{\s*(\w+)\s*\}\}/g, (_, name: string) => String(options[name] ?? ''))
+    }) as TFunction<N>
+  }
+
+  t: TFunction<'common'> = (key, options) => this.getFixedT(this.language, 'common')(key, options)
+
+  changeLanguage(lng: Lang): Promise<void> {
+    if (lng !== this.language) {
+      this.language = lng
+      document.documentElement.lang = lng
+      try {
+        localStorage.setItem(STORAGE_KEY, lng)
+      } catch {
+        // Private mode: the choice just lasts for this tab.
+      }
+      for (const notify of listeners) notify()
+    }
+    return Promise.resolve()
+  }
+
+  subscribe = (notify: () => void): (() => void) => {
+    listeners.add(notify)
+    return () => listeners.delete(notify)
+  }
+}