[run-vm] optional forward ports

currently only allows forwarding to port 80, i was to lazy to handle two
arguments in bash

scripts/run-vm.sh

@@ -6,6 +6,7 @@ usage() {
     echo "--no-disko disable disko and initrd secrets. needed for real hosts like fanny"
     echo "--writable-store enables writable store. necessary for host with nested imperative microvms like fanny"
     echo "--var path to directory that should be shared as /var. may require root otherwise some systemd units fail within vm. if dir is empty vm will populate"
+    echo "--fwd-port forwards the given port to port 80 on vm"
     exit 1
 }
 
@@ -22,6 +23,7 @@ DUMMY_SECRETS=false
 NO_DISKO=false
 RW_STORE=false
 VAR_PATH=""
+FWD_PORT=0
 
 # check argws
 shift
@@ -40,6 +42,15 @@ while [[ "$#" -gt 0 ]]; do
               usage
           fi
           ;;
+        --fwd-port) 
+          if [[ -n "$2" && ! "$2" =~ ^- ]]; then
+              FWD_PORT="$2"
+              shift
+          else
+              echo "Error: --var requires a non-empty string argument."
+              usage
+          fi
+          ;;
         *) echo "Unknown argument: $1"; usage ;;
     esac
     shift
@@ -53,4 +64,4 @@ if [ -n "$VAR_PATH" ]; then
   echo "sharing var directory: $VAR_PATH"
 fi
 
-nix run --show-trace --impure --expr "((builtins.getFlake \"$(pwd)\").vmBuilder.x86_64-linux \"$HOSTNAME\" $NETWORK $DUMMY_SECRETS $NO_DISKO \"$VAR_PATH\" $RW_STORE).config.microvm.declaredRunner"
+nix run --show-trace --impure --expr "((builtins.getFlake \"$(pwd)\").vmBuilder.x86_64-linux \"$HOSTNAME\" $NETWORK $DUMMY_SECRETS $NO_DISKO \"$VAR_PATH\" $RW_STORE $FWD_PORT).config.microvm.declaredRunner"