K-114: set up locales in setup_base_apt (C.UTF-8 during install, en_US.UTF-8 default)

LXC templates ship without a configured locale, so every apt/perl run
warned 'Setting locale failed'. setup_base_apt now exports C.UTF-8 for
the install run itself, installs the locales package, generates
en_US.UTF-8 and sets it as the system default via update-locale.

lib/install.func

@@ -15,10 +15,14 @@ msg_warn() { echo -e "${YELLOW}[!]${NC} $*"; }
 msg_err()  { echo -e "${RED}[✗]${NC} $*" >&2; }
 
 # ── apt ──────────────────────────────────────────────────────────────────────
-# Always installs: ca-certificates curl openssl tzdata gnupg
+# Always installs: ca-certificates curl openssl tzdata gnupg locales
 # Additional packages can be passed as args.
 setup_base_apt() {
   export DEBIAN_FRONTEND=noninteractive
+  # C.UTF-8 ist in glibc eingebaut und damit schon VOR dem locales-Paket
+  # verfügbar — deckt den ersten apt/dpkg-Lauf ab (keine perl-Warnungen
+  # "Setting locale failed" mehr, LXC-Templates kommen ohne Locale).
+  export LANG=C.UTF-8 LC_ALL=C.UTF-8
   msg_info "Updating apt index..."
   apt-get update -qq
   if [[ $# -gt 0 ]]; then
@@ -27,12 +31,24 @@ setup_base_apt() {
     msg_info "Installing base packages..."
   fi
   apt-get install -y -qq \
-    ca-certificates curl openssl tzdata gnupg \
+    ca-certificates curl openssl tzdata gnupg locales \
     "$@" \
     >/dev/null
+  setup_locales
   msg_ok "apt setup complete"
 }
 
+# en_US.UTF-8 generieren und systemweit als Default setzen; C.UTF-8 braucht
+# keine Generierung (glibc-built-in). Idempotent: sed greift nur auf die
+# auskommentierte Zeile, locale-gen/update-locale sind re-run-sicher.
+setup_locales() {
+  msg_info "Generating locales (en_US.UTF-8; C.UTF-8 built-in)..."
+  sed -i 's/^# *en_US\.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen
+  locale-gen >/dev/null
+  update-locale LANG=en_US.UTF-8
+  msg_ok "Default locale: en_US.UTF-8"
+}
+
 apt_cleanup() {
   apt-get autoremove -y -qq >/dev/null || true
   apt-get autoclean -qq >/dev/null || true