fix(docker): uv via standalone installer (#31)

Python 3.12 from deadsnakes on Ubuntu 22.04 drops `distutils` from the
stdlib, and Ubuntu's system pip still imports from it — so `pip install`
fails immediately with ModuleNotFoundError: distutils. Switch to the uv
standalone installer, which doesn't need pip at all.

Caught during the first deploy build.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -30,7 +30,6 @@ RUN apt-get update \
         python3.12 \
         python3.12-venv \
         python3.12-dev \
-        python3-pip \
         libmagic1 \
         libgl1 \
         libglib2.0-0 \
@@ -40,8 +39,10 @@ RUN apt-get update \
  && rm -rf /var/lib/apt/lists/*
 
 # --- uv (dependency resolver used by the project) -----------------------
-RUN python -m pip install --upgrade pip \
- && python -m pip install "uv>=0.4"
+# Install via the standalone installer; avoids needing a working system pip
+# (python3.12 on Ubuntu 22.04 has no `distutils`, which breaks Ubuntu pip).
+RUN curl -LsSf https://astral.sh/uv/install.sh | sh \
+ && ln -sf /root/.local/bin/uv /usr/local/bin/uv
 
 WORKDIR /app