Fork xmrcheckout for Wownero (WOW)

Minimal changes from upstream xmrcheckout to support Wownero:
- Rate provider: Nonlogs WOW-BTC via Kraken BTC/USD
- Subaddress derivation: Wownero network byte overrides (53/63/54)
- Payment URI scheme: wownero:
- Dockerfile: Wownero binaries from Codeberg
- Display text: Monero→Wownero, XMR→WOW throughout UI
- Default daemon: 192.168.88.235:34568
- Added wownero-logo.svg

File and folder structure kept identical to upstream for easy sync.

api/Dockerfile

@@ -0,0 +1,12 @@
+FROM python:3.12-slim
+
+WORKDIR /app
+
+COPY requirements.txt /app/requirements.txt
+RUN pip install --no-cache-dir -r /app/requirements.txt
+
+COPY app /app/app
+
+EXPOSE 8000
+
+CMD ["/bin/sh", "-c", "gunicorn app.main:app -k uvicorn.workers.UvicornWorker -b 0.0.0.0:8000 -w ${GUNICORN_WORKERS:-2}"]