Fix menu requiring double input on Alpine (#38)

read -rsn1 in press_any_key consumes only 1 byte. Multi-byte keys
(arrows, function keys) send escape sequences (e.g. \033[A) — the
remaining bytes leak into stdin and get picked up by the next
read_choice, matching no menu option and causing a silent redraw.

Fix: drain leftover bytes after every read -rsn1 and defensively
at the top of read_choice before accepting user input.

Author: SamNet-dev

mtproxymax.sh

@@ -282,6 +282,8 @@ draw_sparkline() {
 read_choice() {
     local prompt="${1:-choice}"
     local default="${2:-}"
+    # Drain any stale input (e.g., leftover escape-sequence bytes)
+    read -rsn 256 -t 0.05 _ 2>/dev/null || true
     echo -en "\n  ${DIM}Enter ${prompt,,}${NC}" >&2
     [ -n "$default" ] && echo -en " ${DIM}[${default}]${NC}" >&2
     echo -en "${DIM}:${NC} " >&2
@@ -307,6 +309,8 @@ press_any_key() {
     echo ""
     echo -en "  ${DIM}Press any key to continue...${NC}"
     read -rsn1
+    # Drain leftover bytes from multi-byte keys (arrow/function keys send escape sequences)
+    read -rsn 256 -t 0.05 _ 2>/dev/null || true
     echo ""
 }
 
@@ -4516,6 +4520,7 @@ run_installer() {
     echo ""
     echo -en "  ${DIM}Press any key to open the management menu...${NC}"
     read -rsn1
+    read -rsn 256 -t 0.05 _ 2>/dev/null || true
     load_settings
     load_secrets
     show_main_menu