Initial commit: DDNS service with NIC V2 protocol support

Features:
- Token-based subdomain claiming
- NIC V2 (DynDNS2) protocol implementation
- Technitium DNS integration
- Rate limiting (10 req/min IP, 1 req/min token)
- Web UI for space claiming
- Docker/Docker Compose support
- Compatible with UniFi, pfSense, EdgeRouter

Module: git.dws.rip/DWS/dyn

Dockerfile

@@ -0,0 +1,34 @@
+# Build stage
+FROM golang:1.23-alpine AS builder
+
+RUN apk add --no-cache gcc musl-dev sqlite-dev
+
+WORKDIR /app
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+RUN CGO_ENABLED=1 GOOS=linux go build -a -installsuffix cgo -o server cmd/server/main.go
+
+# Runtime stage
+FROM alpine:latest
+
+RUN apk --no-cache add ca-certificates sqlite-libs
+
+WORKDIR /app
+
+COPY --from=builder /app/server .
+COPY --from=builder /app/web ./web
+
+VOLUME ["/data"]
+
+ENV DATABASE_PATH=/data/dyn.db \
+    SERVER_PORT=8080 \
+    RATE_LIMIT_PER_IP=10 \
+    RATE_LIMIT_PER_TOKEN=1
+
+EXPOSE 8080
+
+CMD ["./server"]