Make /opt/moonarch root-owned for multi-user support

Remove chown from archinstall custom-commands so the repo stays
root:root. Use sudo for git operations in update.sh. Any user with
sudo can now run moonarch-update without owning the repo.

scripts/update.sh

@@ -15,17 +15,17 @@ check_not_root
 log "=== Update Moonarch repo ==="
 
 cd "$PROJECT_DIR"
-if git rev-parse --is-inside-work-tree &>/dev/null; then
-    LOCAL=$(git rev-parse HEAD)
-    git fetch origin
-    REMOTE=$(git rev-parse @{u} 2>/dev/null || echo "$LOCAL")
+if sudo git rev-parse --is-inside-work-tree &>/dev/null; then
+    LOCAL=$(sudo git rev-parse HEAD)
+    sudo git fetch origin
+    REMOTE=$(sudo git rev-parse @{u} 2>/dev/null || echo "$LOCAL")
 
     if [[ "$LOCAL" != "$REMOTE" ]]; then
         log "Updates available."
-        git --no-pager log --oneline "$LOCAL".."$REMOTE"
+        sudo git --no-pager log --oneline "$LOCAL".."$REMOTE"
         echo ""
         if confirm "Update repo?"; then
-            git pull --ff-only
+            sudo git pull --ff-only
             log "Repo updated."
         else
             log "Repo update skipped."