Prepare KarlDNS production deployment

Dockerfile

@@ -1,12 +1,13 @@
-FROM python:3.12-slim
+FROM python:3.14-alpine
 
 ENV DDNS_DATABASE=/data/ddns.sqlite3
 
 WORKDIR /app
-COPY pyproject.toml README.md /app/
-COPY router_dyndns /app/router_dyndns
-RUN pip install --no-cache-dir .
-RUN adduser --system --group --home /app karldns \
+COPY pyproject.toml README.md requirements.txt /app/
+COPY karldns /app/karldns
+RUN pip install --no-cache-dir -r requirements.txt . \
+    && addgroup -S karldns \
+    && adduser -S -G karldns -h /app karldns \
     && mkdir -p /data \
     && chown -R karldns:karldns /app /data
 USER karldns