fix(server): rename awk variable 'in' to 'inside' in wg-peerctl remove

'in' became a reserved keyword in GNU awk 5.x causing syntax errors
when removing peers. Peer deletion silently failed as a result.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/wg-peerctl.sh

@@ -408,13 +408,13 @@ cmd_remove() {
   local tmp
   tmp="$(mktemp)"
   awk -v pk="$client_pubkey" '
-    BEGIN {in=0; block=""; keep=1}
+    BEGIN {inside=0; block=""; keep=1}
     /^\[Peer\]/ {
-      if (in && keep) printf "%s", block
-      in=1; block=$0 ORS; keep=1; next
+      if (inside && keep) printf "%s", block
+      inside=1; block=$0 ORS; keep=1; next
     }
     {
-      if (in) {
+      if (inside) {
         block = block $0 ORS
         if ($0 ~ /^PublicKey[[:space:]]*=/) {
           line=$0
@@ -426,7 +426,7 @@ cmd_remove() {
       print
     }
     END {
-      if (in && keep) printf "%s", block
+      if (inside && keep) printf "%s", block
     }
   ' "$WG_CONF" > "$tmp"
   mv "$tmp" "$WG_CONF"