refactor(core): Major update to core functions with validation, IPv6 support, and Debian 13 fixes

- alpine-tools.func: Complete rewrite with simplified structure and better error handling
- build.func: Add comprehensive validation functions (Container-ID, hostname, MAC, VLAN, MTU, IPv6, bridge, gateway, timezone, tags), storage space validation, improved password handling
- core.func: Add ensure_profile_loaded() and get_lxc_ip() functions, improved cleanup_lxc() with fallback error handling
- install.func: Fix Debian 13 LXC template bug (root owned by nobody), integrate get_lxc_ip()
- tools.func: Add IPv6 fallback support, improved NVIDIA GPU detection (including Open Kernel Module), Debian 13 Trixie support, new setup_meilisearch() function, completely reworked MariaDB setup with distribution package fallback

scripts/core/install.func

@@ -37,6 +37,9 @@ source "$(dirname "${BASH_SOURCE[0]}")/error-handler.func"
 load_functions
 catch_errors
 
+# Get LXC IP address (must be called INSIDE container, after network is up)
+get_lxc_ip
+
 # ==============================================================================
 # SECTION 2: NETWORK & CONNECTIVITY
 # ==============================================================================
@@ -76,6 +79,13 @@ EOF
 # ------------------------------------------------------------------------------
 setting_up_container() {
   msg_info "Setting up Container OS"
+
+  # Fix Debian 13 LXC template bug where / is owned by nobody
+  # Only attempt in privileged containers (unprivileged cannot chown /)
+  if [[ "$(stat -c '%U' /)" != "root" ]]; then
+    (chown root:root / 2>/dev/null) || true
+  fi
+
   for ((i = RETRY_NUM; i > 0; i--)); do
     if [ "$(hostname -I)" != "" ]; then
       break