add check_deps function and dependency checks to all scripts

hub/setup-hub.sh

@@ -33,12 +33,27 @@ check_permissions() {
 }
 
 info()   { echo -e "${GREEN}[+]${NC} $*"; }
+check_deps() {
+    local missing=()
+    for cmd in "$@"; do
+        if ! command -v "$cmd" >/dev/null 2>&1; then
+            missing+=("$cmd")
+        fi
+    done
+    if [ ${#missing[@]} -gt 0 ]; then
+        die "Missing required dependencies: ${missing[*]}"
+    fi
+}
+
+
 warn()   { echo -e "${YELLOW}[!]${NC} $*"; }
 die()    { echo -e "${RED}[ERROR]${NC} $*" >&2; exit 1; }
 header() { echo -e "\n${CYAN}══════════════════════════════════════════${NC}"; echo -e "${CYAN}  $*${NC}"; echo -e "${CYAN}══════════════════════════════════════════${NC}"; }
 
 [ "$(id -u)" -eq 0 ] || die "Run as root"
 
+check_deps ssh ssh-keygen systemctl useradd groupadd crontab
+
 header "TinyBoard Hub Setup"
 
 read -rp "Hub username [armbian]: " HUB_USER