v2.4.0 — internationalization (EN/RU) + custom git templates

- i18n engine (lib/i18n.sh, lib/lang/en.sh, lib/lang/ru.sh)
- first-run language picker, persisted to .language + config.json
- install.sh, common.sh, backup.sh, templates_catalog.sh wired through t()/tf()
- backup.sh preserves .language marker and records language in metadata.json
- custom git template feature (first item in pro template picker)
  * validates HTTPS URLs, rejects shell metachars
  * 100MB size guard, 90s clone timeout
  * auto-detects index.html in dist/public/build/_site/site/docs/out/www
- bot v2.4.0: i18n.py + lang/{en,ru}.json, /lang command, language toggle button
- bot: custom git template via text input with waiter gating

lib/i18n.sh

@@ -0,0 +1,140 @@
+#!/bin/bash
+# GoTelegram v2.4 — i18n engine
+# Internationalization support: EN (English) / RU (Русский)
+#
+# Usage:
+#   source lib/i18n.sh
+#   load_language "ru"         # or "en"
+#   echo "$(t menu_install)"   # translated string
+#   printf "$(t greeting)\n" "$name"   # with format args
+
+# ── Global i18n state ──
+declare -gA I18N
+LANG_CODE="${LANG_CODE:-en}"
+LANG_FILE=""
+
+# ── Load a language ──
+# Sources lib/lang/${lang}.sh into the I18N associative array.
+# Falls back to English if requested language file is missing.
+load_language() {
+    local lang="${1:-en}"
+    # Sanitize: only allow [a-z]{2} codes
+    if ! [[ "$lang" =~ ^[a-z]{2}$ ]]; then
+        lang="en"
+    fi
+
+    local lang_dir
+    lang_dir="$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")/lang"
+    local lang_file="${lang_dir}/${lang}.sh"
+
+    if [ ! -f "$lang_file" ]; then
+        lang_file="${lang_dir}/en.sh"
+        lang="en"
+    fi
+
+    if [ -f "$lang_file" ]; then
+        # Clear previous keys then source the new language
+        I18N=()
+        # shellcheck disable=SC1090
+        source "$lang_file"
+        LANG_CODE="$lang"
+        LANG_FILE="$lang_file"
+        return 0
+    fi
+    return 1
+}
+
+# ── Translate: fetch value by key ──
+# t <key>   → echoes translation (or key if missing)
+t() {
+    local key="$1"
+    local val="${I18N[$key]:-}"
+    if [ -z "$val" ]; then
+        # Fallback to key name so missing translations are visible
+        echo "$key"
+    else
+        echo "$val"
+    fi
+}
+
+# ── Translate + printf-style formatting ──
+# tf <key> <arg1> <arg2> ...
+tf() {
+    local key="$1"
+    shift
+    local fmt="${I18N[$key]:-$key}"
+    # shellcheck disable=SC2059
+    printf "$fmt" "$@"
+}
+
+# ── Get current language code ──
+get_language() {
+    echo "$LANG_CODE"
+}
+
+# ── Detect saved language from config.json, default en ──
+detect_language() {
+    local cfg="${GOTELEGRAM_CONFIG:-/opt/gotelegram/config.json}"
+    local lang=""
+    if [ -f "$cfg" ] && command -v jq >/dev/null 2>&1; then
+        lang=$(jq -r '.language // empty' "$cfg" 2>/dev/null)
+    fi
+    # Also check marker file (language set before config.json exists)
+    if [ -z "$lang" ]; then
+        local marker="${GOTELEGRAM_DIR:-/opt/gotelegram}/.language"
+        if [ -f "$marker" ]; then
+            lang=$(head -c 2 "$marker" 2>/dev/null | tr -d '[:space:]')
+        fi
+    fi
+    # Sanitize
+    if ! [[ "$lang" =~ ^(en|ru)$ ]]; then
+        lang="en"
+    fi
+    echo "$lang"
+}
+
+# ── Persist selected language ──
+# Saves to config.json if present, otherwise to marker file
+save_language() {
+    local lang="$1"
+    if ! [[ "$lang" =~ ^(en|ru)$ ]]; then
+        return 1
+    fi
+    mkdir -p "${GOTELEGRAM_DIR:-/opt/gotelegram}" 2>/dev/null
+    # Always write marker for early-access (before config.json exists)
+    echo "$lang" > "${GOTELEGRAM_DIR:-/opt/gotelegram}/.language" 2>/dev/null
+
+    local cfg="${GOTELEGRAM_CONFIG:-/opt/gotelegram/config.json}"
+    if [ -f "$cfg" ] && command -v jq >/dev/null 2>&1; then
+        local tmp
+        tmp=$(mktemp) || return 1
+        if jq --arg lang "$lang" '. + {language: $lang}' "$cfg" > "$tmp" 2>/dev/null; then
+            mv "$tmp" "$cfg"
+            chmod 600 "$cfg"
+        else
+            rm -f "$tmp"
+        fi
+    fi
+    return 0
+}
+
+# ── First-run interactive language picker ──
+# Shows a minimal, language-agnostic picker (keeps it culture-neutral).
+# Returns the chosen code via echo.
+pick_language_interactive() {
+    echo "" >&2
+    echo "  ┌──────────────────────────────────────────┐" >&2
+    echo "  │  Select language / Выберите язык         │" >&2
+    echo "  ├──────────────────────────────────────────┤" >&2
+    echo "  │  1) English                              │" >&2
+    echo "  │  2) Русский                              │" >&2
+    echo "  └──────────────────────────────────────────┘" >&2
+    echo -n "  > " >&2
+    local ch
+    read -r ch
+    case "$ch" in
+        1|en|EN|english|English) echo "en" ;;
+        2|ru|RU|russian|Russian|русский) echo "ru" ;;
+        *) echo "en" ;;
+    esac
+}