feat(docker): add healthcheck and wget dependency

Adds a healthcheck endpoint and updates Dockerfile/README
to include wget and define healthcheck logic.

Dockerfile

@@ -21,7 +21,11 @@ RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o warpbox ./cmd/
 # Stage 2: Runtime
 FROM alpine:3.21
 
-RUN apk add --no-cache ca-certificates tzdata
+RUN apk add \
+    --no-cache \
+    ca-certificates \
+    tzdata \
+    wget
 
 # Create non-root user
 RUN addgroup -S warpbox && adduser -S warpbox -G warpbox
@@ -60,6 +64,9 @@ ENV WARPBOX_DATA_DIR=/app/data \
 
 EXPOSE 8080
 
+HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
+  CMD wget -qO- http://127.0.0.1:8080/health >/dev/null || exit 1
+
 VOLUME ["/app/data"]
 
 CMD ["./warpbox", "run", "--addr", ":8080"]