fix(misc): replace generic return 1 with specific exit codes in remaining .func files

Replace 80 generic 'return 1' error returns with specific exit codes
across alpine-tools.func, build.func, core.func, cloud-init.func,
and vm-core.func, matching the EXIT_CODES.md schema.

alpine-tools.func (51 replaced):
- check_for_gh_release, fetch_and_deploy_gh: API/DNS/download errors
- setup_yq, setup_adminer, setup_uv, setup_java, setup_go, setup_composer
- need_tool, download_with_progress

build.func (13 replaced):
- install_ssh_keys_into_ct: file operation errors (252)
- choose_and_set_storage_for_file: parameter/service errors (65/150)
- _find_default_vars, default_var_settings: file not found (252)
- destroy_lxc, resolve_storage_preselect, select_storage: param errors (65)
- validate_storage_space: hardware/space errors (236)

core.func (9 replaced):
- get_header: download failed (250)
- prompt_select: no options (65)
- check_or_create_swap: dd/mkswap/swapon failures (150), invalid size (65)
- get_current_ip, get_lxc_ip: IP detection failed (6)

cloud-init.func (6 replaced):
- setup_cloud_init: invalid IP/gateway format (65)
- configure_cloud_init_interactive: whiptail missing (127)
- get_vm_ip, wait_for_cloud_init: timeout/connection errors (7/150)

vm-core.func (1 replaced):
- get_header: download failed (250)

Boolean returns (validate_*, is_*, prompt_*, 'no update') kept as return 1.

misc/cloud-init.func

@@ -319,11 +319,11 @@ function setup_cloud_init() {
   if [ "$network_mode" = "static" ]; then
     if [ -n "$static_ip" ] && ! validate_ip_cidr "$static_ip"; then
       _ci_msg_error "Invalid static IP format: $static_ip (expected: x.x.x.x/xx)"
-      return 1
+      return 65
     fi
     if [ -n "$gateway" ] && ! validate_ip "$gateway"; then
       _ci_msg_error "Invalid gateway IP format: $gateway"
-      return 1
+      return 65
     fi
   fi
 
@@ -433,7 +433,7 @@ function configure_cloud_init_interactive() {
   if ! command -v whiptail >/dev/null 2>&1; then
     echo "Warning: whiptail not available, skipping interactive configuration"
     export CLOUDINIT_ENABLE="no"
-    return 1
+    return 127
   fi
 
   # Ask if user wants to enable Cloud-Init
@@ -603,7 +603,7 @@ function get_vm_ip() {
     elapsed=$((elapsed + 2))
   done
 
-  return 1
+  return 7
 }
 
 # ------------------------------------------------------------------------------
@@ -621,7 +621,7 @@ function wait_for_cloud_init() {
 
   if [ -z "$vm_ip" ]; then
     _ci_msg_warn "Unable to determine VM IP address"
-    return 1
+    return 7
   fi
 
   _ci_msg_info "Waiting for Cloud-Init to complete on ${vm_ip}"
@@ -638,7 +638,7 @@ function wait_for_cloud_init() {
   done
 
   _ci_msg_warn "Cloud-Init did not complete within ${timeout}s"
-  return 1
+  return 150
 }
 
 # ==============================================================================