Initial scaffold with per-nameserver DNS monitoring model

Full project structure following upaas conventions: uber/fx DI, go-chi
routing, slog logging, Viper config. State persisted as JSON file with
per-nameserver record tracking for inconsistency detection. Stub
implementations for resolver, portcheck, tlscheck, and watcher.

Dockerfile

@@ -0,0 +1,38 @@
+# Build stage
+FROM golang:1.25-alpine AS builder
+
+RUN apk add --no-cache git make gcc musl-dev
+
+# Install golangci-lint v2
+RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@latest
+RUN go install golang.org/x/tools/cmd/goimports@latest
+
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+# Run all checks - build fails if any check fails
+RUN make check
+
+# Build the binary
+RUN make build
+
+# Runtime stage
+FROM alpine:3.21
+
+RUN apk add --no-cache ca-certificates tzdata
+
+WORKDIR /app
+
+COPY --from=builder /src/bin/dnswatcher /app/dnswatcher
+
+# Create data directory
+RUN mkdir -p /var/lib/dnswatcher
+
+ENV DNSWATCHER_DATA_DIR=/var/lib/dnswatcher
+
+EXPOSE 8080
+
+ENTRYPOINT ["/app/dnswatcher"]