docs: CI additions, localization decision, upstream-merge path now CI-gated

Refs #53 #94 #95 #98

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

LOTUS_FEATURES.md

@@ -26,8 +26,9 @@ Last updated: July 2026.
 17. [Notifications](#notifications)
 18. [Server Integration](#server-integration)
 19. [Infrastructure](#infrastructure)
-20. [Desktop App Features](#desktop-app-features)
-21. [Key Custom Files](#key-custom-files)
+20. [Localization](#localization)
+21. [Desktop App Features](#desktop-app-features)
+22. [Key Custom Files](#key-custom-files)
 
 ---
 
@@ -1408,6 +1409,22 @@ The session persists as ONE atomic `cinny_session_v1` JSON write (previously ~10
 
 ---
 
+## Localization
+
+Lotus Chat is **English-only for now**, by explicit decision (Sept 2026 audit, #53). The i18next
+mechanism (`i18next-browser-languagedetector` + `public/locales/{en,de}.json`, wired in
+`src/app/i18n.ts`) is real and still used by the ~11 upstream-inherited files that call
+`useTranslation()`, but none of the Lotus-added UI (presence picker, calls/soundboard, avatar
+decorations, seasonal settings, keyboard shortcuts help, toasts, etc.) is routed through it. Letting
+the language detector pick a non-English browser locale therefore produced a UI that was only
+partially translated. `src/app/i18n.ts` now sets `supportedLngs: ['en']` so the whole app renders
+consistently in English regardless of browser locale, while leaving the detector/backend/`de.json`
+in place. Re-enabling another language requires two things: (1) route Lotus strings through
+`useTranslation()`/`public/locales/<lng>.json` like the existing localized files, then (2) drop (or
+extend) `supportedLngs` in `src/app/i18n.ts` — a one-line change.
+
+---
+
 ## Desktop App Features
 
 Native capabilities of the Lotus Chat **Tauri v2** desktop app (Windows, macOS, Linux) on top of the shared web client. Web hooks live in `src/app/hooks/useTauri*.ts` (each no-ops in the browser) and call Rust commands in `cinny-desktop/src-tauri/src/native/*`. Windows-only pieces are `#[cfg(target_os = "windows")]`, compile-verified in CI (Windows runners).