feat(docker): display Zeus lndconnect as QR code

- Add qrencode to devenv.nix packages
- Display QR code in terminal for easy Zeus wallet scanning
- Falls back to text if qrencode not available

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker/dev.sh

@@ -339,7 +339,13 @@ show_status() {
 
     if [[ -n "$lndconnect" ]]; then
         echo -e "${CYAN}Zeus Wallet (connect to lnd-3 for testing)${NC}"
-        echo -e "  ${DIM}$lndconnect${NC}"
+        if command -v qrencode &> /dev/null; then
+            echo ""
+            qrencode -t ANSIUTF8 "$lndconnect"
+        else
+            echo -e "  ${DIM}$lndconnect${NC}"
+            echo -e "  ${DIM}(install qrencode for QR code display)${NC}"
+        fi
         echo ""
     fi