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/public/llms.txt

@@ -0,0 +1,15 @@
+# LoVisual
+
+> LoVisual is a free Fabric mod for Minecraft with 80+ visual modules: wings, particles, a custom HUD, weather and 18 built-in themes. It is a visual mod, not a cheat client. This site hosts the download, a browser theme editor, a showcase of community configs and account tools. The site is available in Russian and English.
+
+## Main pages
+
+- [Home](https://visual.loki-code.dev/): what the mod does, live ClickGui and HUD demos
+- [Download](https://visual.loki-code.dev/download): the mod jar and release notes
+- [Themes](https://visual.loki-code.dev/themes): edit and preview ClickGui themes in the browser
+- [Showcase](https://visual.loki-code.dev/showcase): configs and themes published by players
+
+## Notes for crawlers
+
+- [Sitemap](https://visual.loki-code.dev/sitemap.xml): list of public pages
+- Account pages (`/account`, `/configs`, `/link`) require a login and contain nothing public.