feat(http/h2c): h2c test server with a Dockerfile

- Implemented a basic HTTP/2 server that responds with "ok" to requests.
- Updated dev.compose.yml to include a service for it

cmd/h2c_test_server/Dockerfile

@@ -0,0 +1,18 @@
+FROM golang:1.25.5-alpine AS builder
+
+HEALTHCHECK NONE
+
+WORKDIR /src
+
+COPY go.mod go.sum ./
+COPY main.go ./
+
+RUN go build -o h2c_test_server main.go
+
+FROM scratch
+
+COPY --from=builder /src/h2c_test_server /app/run
+
+USER 1001:1001
+
+CMD ["/app/run"]