feat(lib): add require_disk_space helper and enforce pre-flight disk checks

- add `require_disk_space` function to lib/common.sh with dedup logic for shared filesystems
- gate cloudpanel, coolify, pterodactyl installs behind a 2–3 GB disk check
- gate uptime-kuma, proxmox update, harden, update-server, and server-benchmark behind 300–1024 MB disk checks
- fail early with a clear error before apt installs or config writes can leave the system in a partial state

apps/cloudpanel.sh

@@ -220,6 +220,7 @@ install_cloudpanel() {
         return 0
     fi
 
+    require_disk_space 2048 || return 1
     check_requirements || return 1
     echo ""
     

apps/coolify.sh

@@ -67,6 +67,7 @@ install_coolify() {
         return 0
     fi
 
+    require_disk_space 3072 || return 1
     check_requirements || return 1
     echo ""
     

apps/proxmox.sh

@@ -245,6 +245,8 @@ update_proxmox() {
 
     check_proxmox || return 1
 
+    require_disk_space 1024 || return 1
+
     # Configure non-interactive mode
     export DEBIAN_FRONTEND=noninteractive
     export NEEDRESTART_MODE=a

apps/pterodactyl.sh

@@ -212,6 +212,8 @@ install_pterodactyl() {
         return 0
     fi
 
+    require_disk_space 3072 || return 1
+
     echo "[1/10] Installing dependencies..."
     install_dependencies && install_composer
     echo ""

apps/uptime-kuma.sh

@@ -94,6 +94,8 @@ install_uptime_kuma() {
         return 0
     fi
 
+    require_disk_space 1024 || return 1
+
     echo "[1/4] Installing dependencies..."
     install_dependencies
     echo ""

lib/common.sh

@@ -171,6 +171,42 @@ require_debian_ubuntu() {
     fi
 }
 
+# Verify enough free disk space before doing apt installs or writing config.
+# Fails early with a clear message so we don't get half-installed packages or
+# files truncated mid-write when the disk is full.
+#
+# Usage:
+#   require_disk_space                       # 500MB on /var (apt cache + lists)
+#   require_disk_space 1024                  # 1024MB on /var
+#   require_disk_space 1024 /var /opt        # 1024MB on each listed path
+#
+# Duplicate filesystems (e.g. /var on the same fs as /) are checked once.
+require_disk_space() {
+    local min_mb=${1:-500}
+    shift 2>/dev/null || true
+    local paths=("$@")
+    [ ${#paths[@]} -eq 0 ] && paths=(/var)
+
+    local path avail fs seen=" " rc=0
+    for path in "${paths[@]}"; do
+        fs=$(df -P "$path" 2>/dev/null | awk 'NR==2 {print $1}')
+        if [ -z "$fs" ]; then
+            err "Cannot read disk usage for ${path}"
+            rc=1
+            continue
+        fi
+        [[ "$seen" == *" $fs "* ]] && continue
+        seen="$seen$fs "
+
+        avail=$(df -Pm "$path" 2>/dev/null | awk 'NR==2 {print $4}')
+        if [ "${avail:-0}" -lt "$min_mb" ]; then
+            err "Not enough disk space on ${path} (${fs}): ${avail}MB free, ${min_mb}MB required."
+            rc=1
+        fi
+    done
+    return $rc
+}
+
 # Re-exec the current script via sudo if not already root. Preserves env and
 # arguments. Call near the top of a sub-script:
 #   require_root "$0" "$@"

tools/harden.sh

@@ -56,6 +56,7 @@ done
 # ═══════════════════════════════════════════════════════════════════════════
 
 require_debian_ubuntu || exit 1
+require_disk_space 500 || exit 1
 
 # Read the effective Port from sshd_config + any drop-in under sshd_config.d/
 sshd_effective_port() {

tools/server-benchmark.sh

@@ -39,6 +39,8 @@ install_dependencies() {
         echo -e "${YELLOW}[!] sysbench not found, installing...${NC}"
         echo ""
 
+        require_disk_space 300 || return 1
+
         if command -v apt-get &> /dev/null; then
             run_spinner "Updating package list..." "apt-get update -qq"
             run_spinner "Installing sysbench..." "DEBIAN_FRONTEND=noninteractive apt-get install -y -qq sysbench"

tools/update-server.sh

@@ -62,6 +62,8 @@ if ! command -v apt-get >/dev/null 2>&1; then
     exit 1
 fi
 
+require_disk_space 1024 || exit 1
+
 UPGRADE_CMD="upgrade"
 UPGRADE_LABEL="Upgrade installed packages"
 if [ $DO_FULL_UPGRADE -eq 1 ]; then