docker(deps): drop hatch, add nlohmann-json3-dev for scikit-build-core (#2)

dApp-library v0.1.1 replaced the hatchling build backend with
scikit-build-core, which compiles the bundled libiqsaver C++ extension
at install time. The base deps image installed 'hatch' (no longer used)
and lacked nlohmann/json (a new build-time dependency).

- remove 'hatch' from the venv pip install list (keep 'build')
- add 'nlohmann-json3-dev' to the apt layer (cmake and swig are already
  provided later in this image)

Dockerfile-oai-dapp already installs the dApp via 'pip install ".[all]"',
which now drives the scikit-build-core build using these deps.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Thecave3

docker/Dockerfile-deps

@@ -38,6 +38,7 @@ RUN apt-get update && apt-get install -y \
     sudo \
     tini \
     libjson-c-dev \
+    nlohmann-json3-dev \
     libsqlite3-dev \
     libzmq3-dev \
     python3 \
@@ -64,7 +65,6 @@ ENV PATH="/opt/cmake/bin:${PATH}"
 RUN python3 -m venv /opt/venv \
   && /opt/venv/bin/pip install --upgrade pip \
   && /opt/venv/bin/pip install --no-cache-dir \
-    hatch \
     build \
     fastapi \
     uvicorn \